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31st European Conference on Laser Interaction with Matter xxxi

6-10 September, 2010 - Budapest, Hungary ECLIM

• i.1

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©2010 FEMTOLASERS Produktions GmbH XXXI. European Conference on Laser Interaction with Matter ECLIM 2010 6-10 September 2010, Budapest, Hungary

In the year of the 50th anniversary of the invention of lasers the traditional ECLIM is held in the host country of the future Attosecond Facility of the ELI laser, the Extreme Light Infrastructure of the European Community.

BOOK OF ABSTRACTS General information, organization

International Scientific Committee I.B. Foldes, Hungary (Chairman) D.H.H. Hoffmann, Germany A. Caruso, Italy C. Deutsch, France M. Dunne, U.K. S. Eliezer, Israel H. Fiedorowicz, Poland D.H.H. Hoffmann, Germany M. Kalal, Czech Republic O. Krokhin, Russia T. Mendonc;a, Portugal G. Velarde, Spain

Scientific Secretary Peter Dombi Nora Sandor

Local Organizing Committee Zoltan Szokefalvi Nagy (Chair) Angela Barna Gagik Djotyan Peter Racz

Organized by KFKI Research Institute for Particle and Nuclear Physics of the Hungarian Academy of Sciences H-1121 Budapest, Konkoly-Thege M. lit 29-33. Phone: +36 1 3922222 Fax: +36 1 3959151 Homepage: www.rmki.kfki.hu •

Organizing Office: (registration, accommodation, payment) Top Congress Ltd. Address: Palfy u. 14. H-6725 Szeged, Hungary Phone & Fax: +36-62-499-222 e-mail: [email protected] Website of the Conference: http//top-congress.hu/2010/eclim

2 31st ECLIM . 6-10 September, 2010 - Budapest, Hungary c General information, organization )

Main topics of the Conference • High Power Lasers and Ignition Facilities

• Inertial Fusion Energy, Including Fast Ignition

• Hot-Dense Plasma Atomic Processes

• Interactions with Ultrashort Laser Pulses, Attophysics

• Diagnostics

• Equation of State

• Hydrodynamics and Instabilities

• Laser- and Ion Beam Interaction with Matter

• Laboratory Astrophysics

• Novel X-ray and EUV Sources, X-ray Lasers

• Laser Acceleration, Nuclear and Particle Physics with Ultra Intense Lasers

• Innovative Laser Drivers, Short-Pulse Lasers

• Special Session for ELI-Related Activities

Invited speakers Teodora Baeva, Rutherford Appleton Laboratory, UK Ken Barat, Lawrence Berkeley National Laboratory, USA Alain Bourdier, CEA, France Dimitrios Charalambidis, University of Crete, Greece See Leang Chin, University Laval, Canada Dirk Gericke, University of Warwick, UK Leonida A. Gizzi, CNR and INFN - Pisa, Italy Alexander Golubev, Institute for Theoretical and Experimental Physics (ITEP), Russia Hong Jin Kong, KAIST, Korea Elena Koresheva, Lebedev Institute, Russia Matthias Friedrich Kling, Max-Planck-Institut fur Quantenoptik, Germany George Kyrala, Los Alamos National Laboratory, USA Tammy Ma, Lawrence Livermore National Laboratory, USA Mattias Marklund, Umel Universitet, Sweden Gerard Mourou, Institut de la Lumiere Extreme, ENSTA Palaiseau, France David Neely, Rutherford Appleton Laboratory, UK Andrew Ng, University of British Columbia, Canada Gerhard G. Paulus, Institute of Optics and Quantum Electronics, Jena, Germany Charles Kirkham Rhodes, University of Illinois, USA David Ros, LASERIX, France Youichi Sakawa, ILE Osaka University, Japan Guy Schurtz, CELIA, Bordeaux, France John Sethian, Naval Research Laboratory, USA Erik Storm, Lawrence Livermore National Laboratory, USA Toshiki Tajima, Ludwig Maximilian University Germany Hideaki Takabe, ILE Osaka University, lapan Csaba Toth, Lawrence Berkeley National Laboratory, USA Vladimir Zvorykin, Lebedev Institute, Russia

31st ECLIM . 6-10 September, 2010 - Budapest, Hungary 3 General information, organization

Conference Venue Danubius Hotel Gellert**** Address: Szent Gellert ter 1. H-llll Budapest, Hungary Dates: 6 September, 2010 (Monday) - 10 September, 2010 (Friday)

Registration & information desk (Danubius Hotel Gellert****) You should collect your conference documentation (congress kit, final program & abstract booklet, badge) at the registration desk upon your arrival. The registration desk will be open in the lobby of the Hotel as follows:

5 September, 2010 (Sunday) 17:00 - 19.00 6 September, 2010 (Monday) 08:00 - 16:00 7 September, 2010 (Tuesday) 08:00 - 16:00 8 September, 2010 (Wednesday) 08:00 - 14:00 9 September, 2010 (Thursday 08:00 - 16:00 10 September, 2010 (Friday) 08:00 - 12:00

Registration fees (in Euro) before 30 June, 2010 after 30 June, 2010

participants €310 €360 students €250 €250 accompanying persons €250 €250 The fees do not include any kind of insurance. The organizers do not accept liability for personal accidents, losses or damage.

Payment on-site Your final invoice/bill will be completed upon registration. Payments in advance (bank transfer, cheque) will be accepted on your final invoice / bill. Those who did not pay in advance the total sum can pay the difference at the registration by cash. The following currencies will be accepted for payment on site: Euro (EUR) and Hungarian Forints (HUF).

Badge Participants are requested to wear their badges at all times during the conference.

Oral presentation All speakers are requested to come to the ..Speakers desk" located in the registration area and hand in their presentations to the technicians upon arrival. It is expected that the speakers bring their presentations in Pow- erPoint (ppt), or in pdf format. Please bring your presentation on DVD/CD-ROM or on USB memory sticks and check it previewing .with the technical staff. Use embedded pictures and animations only; picture and ani- mation links to the Internet or to other files will not be accessible. If you have any special requirements, please notify the organizers about it well before the conference. An overhead projector will be at your disposal, too.

Poster presentation The poster exhibition will be held in two sessions, on 7th and 9th September. A board, labelled with the poster number will be available to those who present posters. Presenters are requested to display the poster on the designated board before the sessions. Size of the poster board is 100 cm wide and 200 cm high (portrait orientation).

Poster sessions Poster session 1. (P1-P50): 7th September, 16.00—18.00 Poster session 2. (P51-P100): 9th September, 16.00—18.00 We request the presenters to be at their posters during this time.

4 31st ECLIM . 6-10 September, 2010 - Budapest, Hungary Conference program - oral presentations J

Monday, 6th September

9.00-9.15 Opening Ceremony

Opening Session

Chairman: O.N. Krokhin 9.15-9.45 Mo-1. G. Mourou: The Extreme Light Infrastructure: Missions and Challenges 9.45-10.15 Mo-2. G. A. Kyrala: Measuring the implosion symmetry on the NIF laser 10.15-10.45 Mo-3. T. Baeva: Coherent X-rays and fast electrons in relativistic overdense laser-plasmas

10.45-11.15 Coffee break

Chairman: D. Hoffmann 11.15-11.45 Mo-4. Y. Sakawa: Laboratory experiments to study collisionless shock generation in high-power laser produced counter-streaming plasmas 11.45-12.05 Mo-5. P. Heissler: High harmonic generation from solid surfaces with relativistically intense few cycle laser pulses 12.05-12.25 Mo-6. A. Frank: Energy loss and charge-transfer of heavy ions in laser-generated plasma 12.25-12.45 Mo-7. S. Ter-Avetisyan: Laser-based ion acceleration: a short review of experimental evidences

ELI-related Session

Chairman: G. Mourou 14.00-14.30 Mo-8. D. Charalambidis: News and views from the attosecond generation, characterization and applications frontier 14.30-14.50 Mo-9. K. Osvay: Extreme Light Infrastructure: the laser sources and major challenges 14.50-15.10 Mo-10. M. Galimberti: The 10PW OPCPA Vulcan Project 15.10-15.30 Mo-11. L. Drska: Subatomic and frontier physics with ELI beamlines: reality and dreams

15.30-16.00 Coffee break

Chairman: G. Szab6 16.00-16.30 Mo-12. K. Barat: Laser safety at high profile laser facilities 16.30-16.50 Mo-13. D. Ursescu: Spectral coherent combination of ultrashort pulses 16.50-17.10 Mo-14. L. Veisz: Light Wave Synthesizer 20, a versatile front end for multi-PW few-cycle laser systems 17.10-17.30 Mo-15. M. Lucchini: Generation of high-energy isolated attosecond pulses 17.30-17.50 Mo-16. T.J.M. Boyd: Deviations from the universal power law decay of harmonic spectra in ultra-relativistic laser-plasma interactions

19.00- Welcome cocktail

5 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary Conference program - oral presentations J

Tuesday, 7th September

Chairman: C. Barty 9.00-9.30 Tu-1. E. Storm: The National Ignition Facility: the path to ignition and inertial fusion energy 9.30-10.00 Tu-2. G. Schurtz: Shock ignition of high gain inertial fusion capsules 10.00-10.20 Tu-3. S. Eliezer: The comeback of shock waves 10.20-10.40 Tu-4. M. Geissel: Ultrafast 25 keV backlighting for experiments on Z

10.40-11.10 Coffee break

Chairman: J. Sethian 11.10-11.40 Tu-5. M.F. Kling: Near-field enhanced electron acceleration from dielectric nanospheres in intense few-cycle laser fields 11.40-12.10 Tu-6. M. Marklund: QED studies using high-power lasers 12.10-12.30 Tu-7. O. Renner: Ion deceleration in interpenetrating plasma jets 12.30-12.50 Tu-8. C. Labaune: Interaction physics in the context of ICF with the LIL facility

Chairman: Y. Sakawa 14.00-14.30 Tu-9. E.R. Koresheva: An overview of IFE-related technologies developed in Russia 14.30-15.00 Tu-10. A. Ng: Anomalous behavior of femtosecond-laser excited solid 15.00-15.20 Tu-11. V. Rozanov: Evolution model of turbulent mixing under laser thermonuclear target compression 15.20-15.40 Tu-12. U. Zastrau: Exploring warm dense matter by innovative XUV and X-ray plasma spectroscopy 15.40-16.00 Tu-13. H. Ruhl: Simulation of ultra-intense laser-matter interaction: The onset of cascading

16.00- Coffee, POSTER SESSION

6 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Conference program - oral presentations J Wednesday, 8th September

Plenary Session

Chairman: E. Storm 9.00-9.30 We-1. D. Neely: Ion beams - advances in spectral and efficiency control 9.30-10.00 We-2. J. D. Sethian: Inertial Fusion Energy with Krypton Fluoride Lasers 10.00-10.30 We-3. V. D. Zvorykin: Radiation resistance of transmissive optics for IFE reactor chamber and KrF laser driver

10.30-11.00 Coffee break

Parallel Sessions

1. Fast ion production

Chairman: S. Ter-Avetisyan 11.00-11.20 WeSl-1. P. Antici: Beam shaping of laser-generated particles with conventional accelerator devices 11.20-11.40 WeSl-2. Y. Fukuda: Ion acceleration via interaction of intense laser pulse with cluster-gas target 11.40-12.00 WeSl-3. T. Paasch-Colberg: Laser driven ion acceleration using isolated, mass-limited spheres 12.00-12.20 WeSl-4. T. Nakamura: High energy ion generation via magnetic vortex acceleration 12.20-12.40 WeSl-5. M. Burza: Hollow microspheres - A novel target for staged laser-driven proton acceleration 12.40-13.00 WeSl-6. S. D. Kraft: Dose-dependent biological damage of tumour cells by laser- accelerated proton beams

1. X-ray production

Chairman: P. A. Raczka 11.00-11.20 WeS2-l. H. Fiedorowicz: Compact laser-produced plasma EUV sources for processing polymers and nanoimaging 11.20-11.40 WeS2-2. S. Varro: Attosecond shot noise 11.40-12.00 WeS2-3. Ph. Zeitoun: Time-dependant Bloch-Maxwell modelling of lmj, 200 fs seeded soft x-ray laser 12.00-12.20 WeS2-4. L. Nikzad: Study of electrons distribution produced by laser-plasma interaction on x-ray generation 12.20-12.40 WeS2-5. E. Louzon: Samarium space resolved measurements 12.40-13.00 WeS2-6. P. Sharma: Cross focusing of two coaxial Gaussian beams with relativistic and ponderomotive nonlinearity

7 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary Conference program - oral presentations J

Wednesday, 8th September

1. Laser-plasma interactions

Chairman: V. Rozanov 11.00-11.20 WeS3-l. F. Nafari: Genuine two-fluid computations of laser-plasma interaction for generation of nonlinear force driven plasma blocks 11.20-11.40 WeS3-2. M. Kalal: Issues connected with SBS PCM based self-navigation of laser drivers on injected pellets 11.40-12.00 WeS3-3. I. N. Zavestovskaya: Analysis of the laser materials nanostructurization mechanisms 12.00-12.20 WeS3-4. A. N. Starodub: Interaction of low coherent laser radiation with matter 12.20-12.40 WeS3-5. N. E. Andreev: Laser wakefield dynamics and high gradient acceleration of short electron bunches in guiding structures 12.40-13.00 WeS3-6. J. Krasa: Outbursts of fast ions and generation of DD-neutrons by sub-nanosecond laser irradiation at intensities up to 5xl016 W cm"2

14.00- Excursion and conference dinner

8 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary Conference program - oral presentations

Thursday, 9th September

Chairman: H. Fiedorowicz 9.00-9.30 Th-1. C.K. Rhodes: Giant X-ray nonlinearities in the kiloelectronvolt regime 9.30-10.00 Th-2. T. Tajima: Laser acceleration and high field science 10.00-10.30 Th-3. L.A. Gizzi: High Gradient Acceleration with the FLAME Laser at LNF-FRASCATI 10.30-11.00 Coffee break

Chairman: D. Neely 11.00-11.30 Th-4. Cs. Toth: Radiation sources based on laser plasma accelerators 11.30-11.50 Th-5. C. Deutsch: ICF fast ignition with ultra-relativistic electron beams 11.50-12.10 Th-6. B. Shen: Theoretical progresses on electron and ion acceleration and relativistic short-pulse generation at SIOM 12.10-12.30 Th-7. P. S. Foster: Radiation pressure acceleration on Astra Gemini 12.30-12.50 Th-8. O. N. Rosmej: Experiments on the indirect heating of low density aerogels for applications in heavy ion stopping in plasma

Chairman: M. Kalal 14.00-14.30 Th-9. G. G. Paulus: Multiterrawatt peak power generated by the all diode pumped laser - POLARIS 14.30-15.00 Th-10. A. Golubev: Intense ions for high energy density in matter research 15.00-15.20 Th-11. H. J. Kong: Coherent beam combination of wave-front divided 4 beams by phase controlled stimulated Brillouin scattering phase conjugation mirrors toward the realization of a practical laser fusion driver 15.20-15.40 Th-12. M. M. Aleonard: Electron beams accelerated with two TW class lasers: preplasma effect of target materials 15.40-16.00 Th-13. M. Schlanges: Energy relaxation in dense laser-produced two-temperature plasmas

16.00 - Coffee, POSTER SESSION

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 9 Conference program - oral presentations J

Friday, 10th September

Chairman: C. Deutsch 9.00-9.30 Fr-1. T. Ma: Effects of preplasma on hot electron coupling and propagation in cone attached wire targets 9.30-10.00 Fr-2. H. Takabe: High-Energy laser astrophysics with anti-matters produced with ultra-intense lasers — theory, computation, scaling, experimental data and high-energy astrophysics model experiment 10.00-10.20 Fr-3. B. Sharkov: Extreme state of matter physics at FAIR 10.20-10.40 Fr-4. S. Yu. Gus'kov: Ion beam heating for fast ignition

10.40-11.10 Coffee break

Chairman: C. Toth 11.10-11.40 Fr-5. D. Ros: LASERIX: an open facility for developments of soft X-ray and EUV lasers and applications 11.40-12.00 Fr-6. A. Bourdier: Stochastic heating in high intensity laser-plasma interaction. Application to the wake field acceleration process 12.00-12.20 Fr-7. C. Haefner: Accurate offline dispersion measurement of Petawatt-class chirped pulse amplification compressor and stretcher systems 12.20-12.40 Fr-8. N. G. Borisenko: Validation experiments on laser radiation transmission through nearcritical plasma with several spatial scales

Chairman: N.G. Borisenko 14.00-14.30 Fr-9. S. L. Chin: Intense femtosecond laser filamentation science in air 14.30-15.00 Fr-10. D. O. Gericke: Interaction of energetic ions with high-density plasmas 15.00-15.20 Fr-11. E. Balogh: Attosecond pulse generation in noble gases in the presence of extreme high intensity THz pulses 15.20-15.40 Fr-12. P. Racz: Few-cycle surface plasmon enhanced electron acceleration 15.40-16.00 Fr-13. Wei Hong: Ka emission of copper foil targets driven by an ultrashort laser pulse at relativistic regime 16.00 Closing ceremony

10 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Conference program - posters SESSION 1.

High Power Lasers and Ignition Facilities

Pl. M. Kouhi, M. Ghoranneviss, B. Malekynia, H. Hora, N. Azizi: Resonance at cross section increased fusion gain in volume ignition of clean H-"B reaction P2. D.S.Gavrilov. A.G.Kakshin, EA.Loboda: Interferometry of laser pulse wavefront at the output of subpicosecond facility "SOKOL-P" P3. Ondrei Slezak. Hong Jin Kong, Milan Kalal: Stimulated Brillouin scattering phase-locking using a transient acoustic standing wave excited through an optical interference field P4. Brvn Parry. Nicola Booth, Oleg Chekhlov, John Collier, Edwin Divall, Klaus Ertel, Peta Foster, Steve Hawkes, Chris Hooker, Victoria Marshall, David Neely, Rajeev Pattathil, Daniel Symes, Yunxin Tang and Brian Wyborn: Dual-beam operation of the Astra Gemini laser facility

Interactions with Ultrashort Laser Pulses, Attophysics

P5. N.G. Karlykhanov, PA. Loboda, N.A. Smirnov, A. A. Shadrin: Simulation of absorption of femtosecond laser pulses in solid-density copper P6. A.A. Silaev. N.V. Vvedenskii: Ionization-induced excitation of residual current density in a plasma produced by a few-cycle laser pulse P7. A.A. Silaev. M.Yu. Ryabikin, N.V. Vvedenskii: New reduced-dimensionality models for efficient quantum- mechanical description of ultrafast strong-field phenomena P8. E. Irani. Z.Dehghani, R.Sadighi-Bonabi: Photo-dissociation of methane in the strong femtosecond laser field P9. R. Sadighi-Bonabi. Z. Dehghani and E. Irani: The effect of the two tailored femtosecond laser pulses in the enhancement of methane dissociation P10. K. Kovacs. V. To?a, P. Dombi, M. A. Porras: Generating phase-matched high-order harmonics using CEP controlled few-cycle pulses PI 1. M. A. Porras. I. Gonzalo: Dissipative light-bullets in the filamentation of femtosecond pulses P12. M. Faghihi-Nik, M. Ghorbanalilu, B. Shokri: Effects of external magnetic field on harmonics generated in laser interaction with underdense plasma P13. M. Gorbe, A. Borzsonyi, P. Jojart, M. Kovacs, K. Osvay: Independent control of arbitrary orders of dispersion at the high power end of CPA lasers P14. T. J. M. Boyd, R. Ondarza-Rovira: Plasma effects in attosecond pulse generation from ultra-relativistic laser-plasma interactions P15. R. Sh. Alnayli: Development of the RTP crystal applications for Q-switching operation & Second Harmonics Generation PI6. S. Varro: Temporal Talbot effect in propagation of attosecond electron waves P17. S.Zare. R.Sadighi-Bonabi: Optimization of the produced wakefield by two intense short laser pulses P18. Z. Diveki. Ch. Bourassin-Bouchet, D. Guenot, T. Ruchon, S. de Rossi, F. Delmotte, E. Meltchakov, B. Carre and P. Salieres: Attosecond pulse manipulation with chirped multilayer mirrors P19. S. Haessler, Z. Diveki. J. Caillat, W. Boutu, C. Giovanetti-Teixeira, T. Ruchon, T. Auguste, P. Breger, A.

Maquet, B. Carre, R. Taieb, P. Salieres: Molecular orbital imaging using attosecond pulses generated in N2

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 11 c Conference program - posters

Diagnostics

P20. E.A.Bolkhovitinov, M.V.Fedulov, E.V.Grabovsky, A.N.Gritsuk, G.M.Oleinik, A.A.Rupasov. A.S.Shikanov, G.S.Volkov, V.I.Zaitsev: Measurements for the radiation spectra of fast Z-pinches produced at compression of multi-wire arrays on the "Angara-5-1" facility P21. A. Borzsonyi, M. Mero, A. P. Kovacs, M.P. Kalashnikov, K. Osvay: Spectral phase shift and residual angular dispersion of an acousto-optic programmable dispersive filter P22. A. Sengebusch, H. Reinholz and G. Ropke: Modification of K-line emission profiles in laser-created solid-density plasmas P23. C. Plaisir. M. Tarisien, F. Gobet, F. Hannachi, M.M. Aleonard: NATALIE, a multidetector diagnostic to characterize laser produced particle beams: applications P24. D.A. Vikhlvaev. D.S. Gavrilov, A.G. Kakshin, E.A. Loboda, V.A. Lykov, V.Y. Politov, A.V. Potapov, V.N. Saprykin, K.V. Safronov, P.A. Tolstoukhov: Investigation of copper X-ray spectra on SOKOL-P laser facility at intensities of 1017-1019 W/cm2 P25. D. Margarone, J. Krasa, A. Picciotto, A. Velyhan, J. Prokupek, L. Laska, L. Rye, P. Parys, L. Torrisi, P. Musumeci and B. Rus: Time-of-flight technique for detection of fast ions accelerated by high power laser P26. E. Forster. I. Uschmann, O. Wehrhan, U. Zastrau, et al.: Advanced X-ray and XUV optics for plasma spectroscopy P27.1.Gruia. S.Yermolenko, M.I.Gruia, C.Gavrila: Spectral identification of tissue's malignant changes P28. M. Martinkova, M. Kalal, Y.J. Rhee: Analysis of the complex interferometry diagnostics applicability to deuterium clusters spatial density distribution measurements P29. R. Bhar. M. Khan, A.K.Pal: Pulse laser ablated thin film of BN and related diagnostics P30. T. Konigstein. B. Hidding, S. Karsch, O. Willi, G. Pretzler: Electron bunch distance measurement based on driver/witness type plasma wakefield acceleration

Laser- and Ion Beam Interaction with Matter I.

P31. A.A. Fronva, N.G. Borisenko, M.L. Chernodub, Yu.A. Merkuliev, M.V. Osipov, V.N. Puzyrev, A.T. Sahakyan, A.N. Starodub, B.L. Vasin, O.F. Yakushev: X-ray emission characteristics of foam target plasmas P32. A.Qussif, M. Diaf: Laser action on rare earth doped nitride semiconductor thin layers P33. A.S. Qrekhov. N.G. Borisenko, Yu.V. Krylenko, Yu.A. Mikhailov, G.V. Sklizkov: The variation of effective temperature of stochastically heated electrons in laser pulse P34. B. Malekynia: Protons Energy Loss for Laser Fusion driven Ion Acceleration P35. D. N. Wang. Ying Wang: Miniaturized fiber in-line interferometer fabricated by femtosecond laser micromachining P36. E. Yu. Loktionov, A.V. Ovchinnikov, Yu.Yu. Protasov, D.S. Sitnikov: R&D of an experimental technique for condensed media femtosecond laser ablation recoil momentum evaluation in sub-pN-s range P37. E. Yu. Loktionov, A.V. Ovchinnikov, Yu.Yu. Protasov, D.S. Sitnikov: Experimental investigation of condensed media ultrashort laser ablation multifactor processes P38. F. K. Moghadam, M. Hamzehlooei: Analytical study of the thermal lensing and effects in end pumped solid state Nd:YAG laser with a super Gaussian profile

P39. H.Ehsani.A. S.Saghafi, M.Goraneviss: Determination of changes in refractive index and thickness of Si02 thin film on polycarbonate created by Vis-IR laser irradiation P40.1. Kostyukov. E. Nerush, A. Pukhov, V. Seredov: Electron self-injection and acceleration in the bubble regime of laser-plasma interaction P41.1. Kostyukov. E. Nerush: Simulation of QED effects in ultrahigh intensity laser-plasma interaction P42. K. Walia, A. Singh: Relativistic self-focusing of elliptical laser beam in plasma and its effect on plasma wave and second harmonic generation P43. K. Walia. A. Singh: Enhanced Brillouin scattering of elliptical laser beam in a collisionless plasma

12 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 12 c Conference program - posters ) P44. L. Rajaei and B. Shokri: Microwave heating of the ceramic materials by the Gaussian maser beam P45. R. Kh. Gainutdinov, M. A. Khamadeev, A. A. Mutygullina: Electron-positron pairs creation in the field of two strong counterpropagating laser beams and the nonlocality of the photon-photon interaction P46. LA. Borisenko. N.E. Shapkina: Simple characterization method for foams and aerogels of gas-like densities P47. H. Reinholz, T. Raitza, G. Ropke, I. Morozov: Collective modes of laser excited electrons in clusters

ELI-related activities

P48. N. Elkina, H. Ruhl: Consistent inclusion of radiation reaction into kinetic plasma modeling P49. S.C. Singh: Higher harmonic generation through laser produced plasma P50. S.C. Singh, R. Gopal: Optical Emission Spectroscopic Study of Laser Induced Zinc and Cadmium Plasma

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 13 c Conference program - posters

SESSION 2.

Inertial Fusion Energy, Including Fast Ignition

P51. A.A.Belolipetskiv. E.R.Koresheva, I.V.Aleksandrova, A.N.Aleksandrov, E.L.Koshelev, V.A.Kalabuhov, E. A.Malinina, I.E.Osipov, L.V.Panina, A.I.Safronov, K.O.Semenov, T.P.Timasheva, I.D.Timofeev, G. S.Usachev: FST-formation of cryogenic layer inside spherical shells of HiPER-class: results of mathematical modeling and mock-ups testing P52. Anle Lei, L. H. Cao, K. A. Tanaka, R. Kodama, X. T. He, K. Mima, T. Nakamura, T. Norimatsu, W. Yu, W. Y. Zhang: Fast electron transport in shaped solid targets P53. C. Deutsch. D. Leger, B. Yashev: Low velocity ion slowing down in a demixing binary ionic mixture P54. C. Spindloe: The production of advanced fast ignition cone geometries for fusion studies P55. J. Pasley: Ignition and burn in contaminated DT fuel at high densities P56. M. Ghoranneviss, B. Malekynia, H. Hora, G.H. Miley, A. H. Sari: Laser fusion energy from p-7Li with minimized radioactivity P57. M. Hata, H. Sakagami, T. Johzaki, A. Sunahara, H. Nagatomo: Analysis of effects of laser profiles on fast electron generation by two-dimensional Particle-In-Cell simulations P58. N. Azizi, B. Malekynia, M. Ghoranneviss, A. Mohammadian, M. Kouhi, Z. Abdollahi, H. Hora, G.H. Miley: He3-He3 fusion energy with negligible radioactive emission by block ignition with petawatt- picosecond laser pulses P59. N.R. Minkova: The role of finite instrumental resolution scales in plasma modeling Hot-Dense Plasma Atomic Processes P60. S.V. Gagarin, M.V. Kobel'kova, S.V. Koltchugin, P.A. Loboda.S.V. Morozov, V.V. Popova, A.A. Shadrin, I. Yu. Silantieva, I.V. Solomina, I.A. Vanina, M.A. Vorobyova, A.Ya. Faenov, A.I. Magunov, T.A. Pikuz, I. Yu. Skobelev, I. L. Beigman, F.F. Goryaev, A.M. Urnov, I.Yu. Tolstikhina, L. A. Vainshtein: Calculations of multielectron-ion atomic data and opacities of hot dense plasmas and relevant database developments

Equation of State

P61. K. V. Khishchenko: Equations of state and melting of metals under intense ultrashort laser influences P62. N.V. Zhidkov, V.V. Vatulin, A.G. Kravchenko, P.G. Kuznetsov, D.N. Litvin, V.V. Mis'ko, A.V. Pinegin, N. P. Pletenev, A.V. Senik, K.V. Starodubtsev, G.V. Tachaev: The velocity measurement of shocks generated by x-ray radiation in different materials at "Iskra-5" laser P63. S. A. Bel'kov, I.N. Voronich, S.G. Garanin, V.N. Derkach. G.G. Kochemasov, D.N. Litvin, S. A. Sukharev: The EOS studies on Luch facility P64. A. Yu. Voronin, S.G. Garanin, V.N. Derkach, N.V. Zhidkov, A.G. Kravchenko, N.A. Petrazhitskaya, K.V. Starodubtsev, S.A. Sukharev, R.A. Shnyagin: Development of the systems for uniform target irradiation

Hydrodynamics and Instabilities

P65.1. V.Romanov, A.A.Rupasov, A.S.Shikanov,V.L.Paperny.A.Moorti. R.K.Bhat, P.A.Naik, P.D.Gupta: Flux of multiple charged metal ions from plasma of a low voltage laser-induced vacuum discharge P66. L. Mandal, R.Banerjee, S.Roy, M.Khan, M.R.Gupta: Effect of magnetic field on ablatively driven Richtmyer - Meshkov instability induced by interfacial nonlinear structure P67. M. Khan. M.R.Gupta, L.K.Mandal, S.Roy, R.Banerjee: Laser induced ablatively driven interfacial nonlinear fluid instabilities in multilayer targets

14 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 14 c Conference program - posters

P68. R. Baneriee, M. Khan, L. K. Mandal, S. Roy, M. R. Gupta: Effect of viscosity and surface tension on the growth of Rayleigh-Taylor Instability and Richtmyer-Meshkov instability under nonlinear domain P69. N. Gambino, D. Mascali, S. Tudisco, A. Anzalone, A. Bonanno, S. Gammino, R. Grasso, D. Leanza, F. Musumeci, L. Neri, S. Privitera, A. Spitaleri: Internal structures of laser generated plasma plumes

Laser- and Ion Beam Interaction with Matter II.

P70. H. Fiedorowicz, A. Bartnik, K. Jach, R. Jarocki, J. Kostecki, M. Szczurek, R. Swierczyriski, P. Wachulak: Interaction of nanosecond EUV pulses with organic polymers P71. M. Habibi: The effect of relativistic self-focusing and ramp density profile on the Plasma Wakefield Accelerators (PWFA) P72. P.Parvin and M.Keraii: Dose dependent damage on fused silica based on micro crack formation due to single and multiple laser shots P73. M. Stafe, C. Negutu, M. Mihailescu, S. S. Ciobanu, N.N. Puscas: A spectroscopic approach for analyzing

the laser drilling of LiNb03 P74. M.V.Osipov, V.G. Dmitriev, V. N.Puzyrev, A.T.Sahakyan, A.N.Starodub, B.L.Vasin: Conversion of Nd- glass laser multimode radiation into the second harmonic P75. P. Parvin. B. Sajad, S. Z. Shoursheini: Measurements of the laser induced plasma parameters for the identification of various metal targets P76. P. Sharma and R.P. Sharma: Suppression of stimulated Raman scattering due to localization of electron plasma wave in laser beam filaments P77. P. Sperling, R. Thiele, M. Chen, Th. Bornath, R.R. Faustlin, C. Fortmann, S.H. Glenzer, W.-D. Kraeft, A. Pukhov, S. Toleikis, Th. Tschentscher, and R. Redmer: Time resolved Thomson scattering on inhomogeneous targets P78. R. Bordoloi. R. Bora: Laser induced nutation and production of quantum superposition state P79. S. Z. Shoursheini. P. Parvin, B. Sajad: The ablation rate measurements of metal targets in laser marking

using double beam irradiation including Q-SW Nd:YAG and CW-C02 laser P80. A. Kasperczuk, T. Pisarczyk, J. Badziak, S. Borodziuk, T. Chodukowski. P. Parys, J. Ullschmied, E. Krousky, K. Masek, M. Pfeifer, K. Rohlena, J. Skala, P. Pisarczyk: Interaction of two Cu plasma jets produced successively from the cylindrically shaped massive target P81. Th. Bornath. T. Doppner, C. Fortmann, S.H. Glenzer, G. Gregori, B. Hoist, W.-D. Kraeft, H.J. Lee, V. Schwarz, P. Sperling, R. Thiele, R. Redmer: X-ray Thomson scattering in strongly correlated plasmas P82. P. Hilse, Th. Bornath, M. Moll, M. Schlanges: Dense xenon nanoplasmas in intense laser fields P83. V.N.Puzyrev. A.A.Fronya, M.V.Osipov, A.T.Sahakyan, A.N.Starodub, B.L.Vasin, O.F.Yakushev: Evolution of plasma emission on second harmonic frequency of Nd-glass laser radiation P84. S.Z. Mortazavi, P.Parvin, A. Reyhani, A. Nozad Golikand, S. Mirershadi: Comparison between carbon nanostructures generated in water by ArF excimer laser and Q-switched Nd:YAG laser

Novel X-ray and EUV Sources, X-ray Lasers

P85. N. Kawashima, H. Muramatsu, C. Yanagimoto, M. Miyazawa, E. Kajiwara: Femtosecond laser produced high intensity X-ray source for the pin-point treatment of cancers P86. Y.-Y. Yang. S.L. Stebbings, F. Stifimann, M. Durach, D. Lehr, W. Schneider, I. Pupeza, J. Raster, O. Pronin, Z.-S. Zhao, X.-M. Duan, M.I. Stockman, E.-B. Kley, E. Fill, F. Krausz, M.F. Kling: Engineering nanostructures for MHz XUV light sources

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 15 c Conference program - posters

Laser Acceleration, Nuclear and Particle Physics with Ultra Intense Lasers

P87. D.V.Torshin, V.A.Lykov: The 3D computer simulation of 200 MeV proton beam generation at the interaction of PW-laser radiation with low-density targets P88. E.Yazdani. H.Hora, R.Sadighi-Bonabi, H.Afarideh: Hydrodynamics computation of ion accelerated in interaction of laser with preformed plasma P89.1. Metzkes, K. Zeil, S. D. Kraft, M. Bussmann, T. E. Cowan, T.Kluge, U. Schramm: Ultrashort pulse laser acceleration of protons P90. M. Fanaei. Sh. Rahmatallahpur, R. Sadighi-Bonabi: Improving the predicted potential and energy of the monoenergetic electrons in an alternative ellipsoid bubble model P91. M. Fanaei, L. Nikzad, R. Sadighi-Bonabi: Calculation of X-ray emission produced by a quasi- monoenergetic electron distribution P92. L. Drska, V. Hanus, M. Sinor: New laser-driven nuclear excitation studies: concepts and proposals P93. N. Vogel. V.A. Skvortsov: Laser magneto-cumulative accelerator of charged particles P94. J. Badziak, S. Jablonski, P. A. Raczka: Ultra-intense proton beams driven by laser-induced cavity pressure P95. P. A. Raczka: Plasma effects in the high-intensity laser driven electron-positron production on a thin foil P96. R. Sadighi-Bonabi, P. M. Ara, M. Moshkelgosha, H. A. Navid: Electromagnetic fields of ultra short laser pulse propagations and density changes in the ramped density plasma P97. S. Borodziuk, A. Kasperczuk, T. Pisarczyk, J. Badziak, T. Chodukowski, J. Ullschmied, E. Krousky, K. Masek, M. Pfeifer, K. Rohlena, J. Skala, P. Pisarczyk: Cavity Pressure Acceleration - an efficient laser-based method of production of high-velocity macroparticles

Innovative Laser Systems, Short-Pulse Lasers

P98. Sh. lam, F. Izadi: Pulsed laser deposition simulation for graphite target using Monte-Carlo method P99.1. B. Foldes. A. Barna, D. Csati, S. Szatmari: Plasma mirror for cleaning KrF laser pulses P100. T. Nagv. W. Schweinberger, A. Sommer, M. Schultze, R. Kienberger, F. Krausz, P. Simon: Novel hollow fiber compressor for high power, multi-mj ultrafast lasers

16 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 16 Abstracts - oral presentations c Abstracts - oral presentations )

Mo-l. The Extreme Light Infrastructure: Missions and Challenges G. Mourou Institut Lumiere Extreme, ENSTA, Palaiseau, 91761, France

ELI will be the first facility in the world dedicated to laser-matter interaction at unprecedented intensity levels. It will be also the first large scale infrastructure based in the eastern part of the European Community. It will explore ultrafast phenomena in the attosecond-zeptosecond domain and will be the gateway of a new regime in laser-matter interaction: the ultra relativistic regime that could reach into Nonlinear Quantum Electrodynamics, where vacuum polarization and elementary particle from vacuum can be produced. ELI's scientific mission will be a holistic investigation of the structure of matter, from atoms to vacuum. If the laser revolutionized atomic physics during the first fifty years, ELI in the same way could revolutionize nuclear physics. At the same time, it will also promote new technologies such as Relativistic Microelectronic with the development of compact laser-accelerators delivering very high-energy particles that could reach the lOOGeV level and photon sources in the MeV regime. ELI will have a large societal benefit offering in medicine new radiography and hadron therapy methods. It will also considerably contribute to material science with the possibility to unravel and slow down the aging process in nuclear reactor and in the environment by offering new ways of identifying radioactive elements.

Mo-2. Measuring the implosion symmetry on the NIF laser George A. Kyrala Los Alamos National Laboratory Los Alamos, NM 87545, USA

Indirect drive is used to implode capsules in cryogenically cooled hohlraums at the National Ignition Facility. One of the required conditions for successful implosion is spherical symmetry of the imploded capsule at peak compression. Instead of using ignition capsules with frozen D/T fuel, analog capsules called symcaps are .used to study the hydrodynamic behavior of the implosion. The symcaps are imploded in hohlraums with the same size, gas fills, and hohlraum gas temperatures of an ignition hohlraums. Symcaps with gaseous fills of deuterium/helium fills are used to emulate the behavior of the ignition capsules. We will describe the technique[l,2] used to measure the symmetry of the implosion of symcaps, show some of the results of the measurements, how the technique was used to tune the symmetry of the implosion, and briefly discuss the extension of the technique to non-igniting capsules filled with mixtures of T/H/D gases. Acknowledgements This work was performed by Los Alamos National Laboratory under the auspices of the U. S. Department of Energy under contract No. DE-AC52-06NA25396. References [1] N. M. Hoffman, D. C. Wilson, M. J. Edwards, D. H. Kalantar, G. A. Kyrala, S. R. Goldmanl, S. V. Weber, N. Izumi, D. A. Callaha2, N. Meezan, N. D. Delamater, I. L. Tregillis, M. J. Schmitt, P. A. Bradley, A. Seifter, O. S. Jones, J. L. Milovitch, C. A. Thomas, Journal of Physics: Conference Series 112 (2008) 022075. [2] Nelson M. Hoffman, Douglas C. Wilson, and George A. Kyrala, Review of Sci. Instrum, 77,10E705(2006).

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Mo-3. Coherent X-rays and fast electrons in relativistic overdense laser-plasmas T. Baeva Rutherford-Appleton Laboratory, U.K.

Laser technology has recently made accessible relativistic intensities, which drive electrons nearly to the speed of light, making laser-matter interaction a highly non-linear collective process. In this talk we consider the reflection and absorption of light from overdense plasma in the relativistic regime. We show that the physical mechanism explaining the generation of coherent X-rays in the reflected radiation is also responsible for absorption and injection of high energy electrons into the plasma. The relativistic electrons are collected by the zero points of the vector potential and driven out of the plasma in specular direction, causing the generation of coherent X-ray radiation. Under the influence of the Coulomb attraction to the plasma ions, the electrons are pulled back and leave the rear side of the plasma in the direction of laser propagation. The influence of laser light pressure is not sufficient to explain the effects discussed.

Mo-4. Laboratory experiments to study collisionless shock generation in high-power laser produced counter-streaming plasmas Y. Sakawa1. Y. Kuramitsu1, T. Morita1, H. Aoki1, H. Tanji1, T. Ide1, N. Ozaki1, R. Kodama'.T. Sano1, K. Shigemori1, T. Norimatsu1, T. Kato1, J. Waugh2, N. Woolsey2, B. Loupias3,A. Diziere4, C. Gregory4, M. Koenig4, Y. Zhang5, X. Liu5, S. Wang5, Q. Dong5, Y. Li5,J. Zhong6, J. Zhang7, and H.Takabe1 'Osaka University, Suita, Osaka, 565-0871, Japan; ^Department of Physics, University of York, Heslington, YOlO 5DD, UK; 3CEA, DAM, DIF, F-91297 Arpajon, France; 4LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128 Palaiseau, France; 5Beijing National Laboratory for Condensed Matter Physics,Institute of Physics, Chinese Academy of Sciences Beijing 100190, China; 61he National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China; 'Shanghai Jiao Tong University, Shanghai 200240, China

Collisionless shocks are often observed by satellites in space plasmas, e.g., the Earth's bow shock and inter- planetary shocks. Large amplitude turbulent waves and energetic particles are also observed in the shock environments. Diffusive shock acceleration and surfing acceleration are considered to be standard models for non-thermal acceleration of energetic particles or cosmic rays in the universe. In space plasmas the electric and magnetic fields and plasma distribution functions, essential to understand the acceleration processes, have been recorded on satellite observatories, such as the Geotail spacecraft. In astrophysical plasmas there is no way to directly measure the key quantities to investigate the shock dynamics and the particle acceleration. The only thing one can observe is the X-ray emission from the vicinity of the shock front. However, there are significant uncertainties in the physics surrounding particle acceleration by collisionless shocks. A laboratory experiment can be an alternative approach to study collisionless shocks and particle acceleration. In this paper we investigate laboratory experiments to study collisionless shock generation in counter- streaming plasmas using Gekko XII HIPER laser system (352 nm (3 co), 500 ps, -100 I / beam, one or four beams, < 1015 W/cm2) at Institute of Laser Engineering, Osaka University. Two types of double-plane targets, Jet and Ablation types were used. In the Jet (Ablation) type, 10 m (60 /im) and 60 ii m thick CH planes were placed with the separation of 4.5 mm; beams were irradiated on the 1st CH and a rear-side (an ablation) plasma is formed, and the plasma from the 2nd CH is created by radiation and/or plasmas from the 1st CH. The plasmas and shocks were diagnosed transverse to the main laser propagation direction; shadowgraphy and modified Nomarski interferometry using a probe laser with ICCD and streak cameras, and SOP and GOI using a visible (450 nm) self-emission. Counter-streaming plasmas were produced, and shock waves were observed. The width of the transition region is much shorter than ion-ion mean-free-path. A particle-in-cell simulation has predicted generation of an electrostatic shock.

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 19 c Abstracts - oral presentations

We also investigate an experimental proposal to demonstrate the formation of high Mach-number collisionless shocks through the self-generated magnetic fields due to nonlinearity in the growth of the Weibel instability.

Mo-5. High harmonic generation from solid surfaces with relativistically intense few cycle laser pulses P. Heissler1. J. Mikhailova1, R. Horlein1, M. Stafe2, D. Herrmann1, R. Tautz1, A. Buck1, K. Schmid1, C. M. S. Sears1, S. G. Rykovanov3,1. B. Foldes4, K. Varju5, L. Veisz1, M. ZepP, F. Krausz1, G. D. Tsakiris1 'Max Planck Institute of Quantum Optics, Garching, Germany 2Dept. of Physics, University „Politehnica" of Bucharest, RO-060042 Bucharest, Romania ^Department of Physics, Ludwig-Maximilians-Universitat, Munich, Germany 4KFKI-Research Institute for Particle and Nuclear Physics, H-1525 Budapest, Hungary 5University of Szeged, Department of Experimental Physics, H-6720 Szeged, Hungary department of Physics and Astronomy, Queens University Belfast, Belfast, UK

Coherent high harmonic radiation from the interaction of intense femtosecond laser pulses with solid targets [1-3] promises the generation of attosecond pulses [4] orders of magnitude more intense than those generated from gaseous media. Such pulses would, for the first time, enable researchers to explore a whole new class of attosecond time resolution XUV-pump XUV-probe type experiments not accessible with the relatively weak gas-harmonic sources available today [5], Two mechanisms can contribute to the generation of high harmonics from solid surfaces, namely coherent wake emission (CWE) and the relativistic ally oscillating mirror (ROM). We present experimental results giving deeper insight into the CWE mechanism. Variations of the chirp, the carrier envelope phase and the polarization of the incident laser pulse all show to drastically influence the emitted harmonic spectra. By analyzing these spectra better understanding of the motion of the electrons at the target surface during the interaction can be achieved. At the same time we show the first observation of ROM harmonics generated by a relativistically intense few cycle laser pulse (8 fs, 150 mj). The broad, almost continuous shape of the recorded harmonic spectra suggests, that the emission of attosecond pulses is limited to only very few cycles around the peak of the envelope of the driving laser pulse what can be explained by strong intensity gating effects. The limitation of the harmonic emission to only very few, down to a single laser cycle is opening the path towards the generation of ultra-intense single attosecond pulses with novel high power, few cycle laser systems and especially interesting in the prospect of ELI. References: [1] G. D. Tsakiris et al., New J. Phys. 8, 19 (2006). [2] T. Baeva et al., Phys. Rev. E 74,046404 (2006). [3] F. Quere et al, Phys. Rev. Lett. 96,125004 (2005). [4] Y. Nomura et al., Nature Phys. 5 (2), 124-128 (2009). [5] T. Brabec and F. Krausz, Rev. Mod. Opt. 72 (2), 545 (2000).

20 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 20 c Abstracts - oral presentations )

Mo-6. Energy loss and charge-transfer of heavy ions in laser-generated plasma A. Frank1, A. Blazevic2, M. Basko6, W. Cayzac1, T. Hefiling2, K. Harres1, D. Kraus1, J. Menzel1, F. Niirnberg1, A. Otten1, A. Pelka1, M. Schollmeier1, A. Schokel1, D. Schumacher1, A. Tauschwitz7, V.V. Vatulin5, O.A. Vikurnov5, P.L. Grande4, G. Schiwietz3 and M. Roth1 °TU Darmstadt, Schlossgartenstrafie 9, D- 64289 Darmstadt, Germany bGSI Helmholtzzentrum fur Schwerionenforschung, Planckstr. 1, D-64291 Darmstadt, Germany 'Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Str. 15, D-12489 Berlin, Germany dUniversidade Federal do Rio Grande do Sul, Porto Allegre, Brazil 'VNIEFF Sarov, Russia fITEP, Moscow, Russia zUniversitat Frankfurt, Senckenberganlage 3, D-60325 Frankfurt, Germany

A detailed understanding of interaction phenomena of intense ion- and laser radiation with matter is important for a large number of applications in different fields of science, from basic research of plasma properties to application in energy science. Energy loss processes of heavy ions in plasma and cold matter are important for the generation of high energy density states in general and especially in the hot dense plasma of an inertial fusion target. At GSI the plasma physics group is investigating the interaction processes of swift ions penetrating laser- generated plasma. The plasma target is created by direct laser irradiation of a target foil. This scheme produces high plasma temperatures and hence high ionization degrees. We present an overview on recent results and developments of beam plasma interaction processes studied with an Ar and Ca ion beam from the GSI accelerator facilities penetrating a laser-generated carbon plasma. A new spectrometer based on CVD diamond was developed for measuring the projectile charge state distribution exiting the target and energy loss at the same time. The experiments carried out on very thin carbon foils resulted in cross sections for the charge transfer processes. These cross sections (from cold matter) were recalculated for plasma conditions (ionized target atoms, free electron gas) to be able to predict the heavy ion charge state evolution in the plasma. The combination of the projectile charge states and the corresponding stopping power S(q) in carbon plasma calculated by a modified version of the CasP [1] code allows to reproduce the measured energy losses and charge distributions and consequently to explain the differences between hot and cold matter [2]. A detailed study on the inhomogeneities imprinted on the plasma by the heating laser has been performed by 2D hydrodynamic simulations which is able to explain the first decrease of the energy loss during the laser-plasma interaction which has been not understood until recently. References [1] http://www.hmi.de/people/schiwietz/casp.html (2009) [2] A. Frank, A. Blazevic et al, Phys. Rev. E 81, 026401 (2010)

21 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Mo-7. Laser-based ion acceleration: a short review of experimental evidences S. Ter- Avetisvan1. R. Prasad1, D. Doria1, K.E. Quinn1, L. Romagnani1, P. Gallegos2,3, P.S. Foster1,2, C.M. Brenner2'3, J.S. Green2, M.J.V. Streeter2, D.C. Carroll3, O. Tresca3, N. Dover4, CA.J. Palmer4, J. Schreiber4, D. Neely2-3, Z. Najmudin4, P." McKenna3, M. Zepf1, and M. Borghesi1 ' School of Mathematics and Physics, Queen's University Belfast, Belfast, UK 2CLF, Rutherford Appleton Laboratory, STFC, Oxfordshire, UK 3SUPA Department of Physics, University of Strathclyde, Glasgow, UK 4The Blackett Laboratory, Imperial College, London, UK

Recent advances in laser technology have led to laser systems with high contrast and extreme intensity values, which have opened up new perspectives in the field of laser-matter interactions. We will discuss recent results obtained in the high power (300 TW) Astra-GEMINI laser system at the Rutherford Appleton Laboratory (RAL). These development enabled access to unprecedented intensities (above 1020 W/cm2), an order of magnitude higher than the previously achieved with ultra-short (~ 50 fs) laser pulses. The interaction of such an intense and high contrast (~ 1010) laser pulses with matter still has to be explored carefully and the experiments aiming to obtain scaling laws or conversion efficiencies are essential. The measurements provided for the first time the opportunity to extend scaling laws for the acceleration process in the ultra-short regime beyond the 1020 W/cm2 threshold, and to access new ion acceleration regimes. Comprehensive on-line diagnostics with high resolution led to a full characterization of the ion emission process and accelerated beam characteristics. The scaling of accelerated proton energies was investigated by varying a number of parameters such as target thickness (down to 10 nm), target material (C, Al), laser light polarization (circular and linear) and angle of laser incidence (oblique - 35°, and normal). A pronounced increase in the ion energies has been observed for ultra-thin targets (10 - 100 nm) at normal laser incidence, with peak energies (~ 20 MeV for protons, ~ 240 MeV for C) significantly higher than previously reported with ultrashort laser pulses. The transition to a "new" regime of ion acceleration, the so-called Radiation Pressure Acceleration (RPA) regime, was also identified, showing quasi-monoenergetic proton spectra and a more favorable ion energy scaling with laser intensity. The experiment was carried out in the framework of the LIBRA project.

Mo-8. News and views from the attosecond generation, characterization and applications frontier P. Tzallas1, J, Kruse1,2, E. Skatzakis1,2, Y. Nomura3, R. Horlein3, C. Kalpouzos1, G.D. Tsakiris3 and D. Charalambidis1,2 1 FORTH-IESL, PO Box 1527, GR711 10 Heraklion, Greece department of Physics, Univ. of Crete, PO Box 2208, GR71003 Heraklion, Greece 3Max-Planck-Institutfiir Quantenoptik, D-85748 Garching, Germany

We report on recent results in the generation, characterization and applications of energetic attosecond pulse trains and ultra-broad coherent XUV continua [1]: 1) Generation: la) We report experimental results confirming contribution of both long and short trajectories in on-axis harmonic generation before, at and after an atomic gas jet, i.e. under three different phase matching conditions. The contribution of both trajectories is manifested through their interference leading to a modulated harmonic (and side band) yield as a function of the driving intensity. lb) We report the generation of sub-fs pulse trains at the 40(aJ pulse energy level from laser surface plasma, measured through 2nd order intensity volume autocorrelation (2nd order IVAC) [2], 2) Characterization: We present comparative studies between RABITT and 2nd order IVAC in on axis harmonic generation before, at and after an atomic gas jet. We find that the two techniques give fairly different results that are compatible with the differently weighted but unavoidable presence of the long and short trajectory in the generation process in all three phase matching conditions. We show that the relative contributions of the two

22 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

trajectories can be estimated through RABITT measurements, while spatiotemporal mean pulse durations can be extracted from 2"d order IVAC traces. 3) Applications: 3a) We present time resolved VUV spectroscopy of ultrafast dynamics in molecular ethylene [3]. 3b) We present time resolved XUV spectroscopy at the lfs temporal scale and ultra-broad band XUV Fourier Transform Spectroscopy in a manifold of doubly excited autoionizing and inner-shell Auger decaying states excited simultaneously through a coherent broadband XUV continuum. Acknowledments This workis supported in part by the European Community's Human Potential Program under contract MTKD- CT-2004-517145 (X-HOMES), the Ultraviolet Laser Facility (ULF) operating at FORTH-IESL (contract HPRI- CT-2001-00139), the ELI research infrastructure preparatory phase program, the FASTQUAST ITN, and the FLUX program of the 7th FP. References [1] P. Tzallas, et al. Nat. Phys. 3, 846 (2007); E. Skantzakis, et al. Opt. Lett. 34,1732 (2009). [2] Y. Nimura, et al. Nature Physics 5, 124 - 128 (2009) [3] A. Peralta Conde, Phys. Rev. A79 (R), 061405 (2009)

Mo-9. Extreme Light Infrastructure: the laser sources and major challenges J-P. Chambaret1, O. Chekhlov2, G. Cheriaux3, J. Collier2, R. Dabu4, P. Dombi5, A.M. Dunne2, K. Ertel2, P. Georges6, J. Fiilop7, J. Hebling7, J. Hein8, C. Hernandez-Gomez2, C. Hooker2, S. Karsch910, G. Korn9, F. Krausz910, C. Le Blanc11, R. Lopez-Martens3, Zs. Major910, F. Mathieu', T. Metzger9, G. Mourou1, P. Nickles12, K. Osvav"3. B. Rus14, W. Sandner12, G. Szabo13, D. Ursescu4, K. Varju13 'Institute de Lumiere Extreme, ENSTA, CNRS, Chemin de la Huniere, Palaiseau Cedex, France 2Central Laser Facility, Ruherford Appleton Laboratory, Chilton, Oxon, U.K. 3LOA, ENSTA, CNRS, Chemin de la Huniere, Palaiseau Cedex, France 4National Institute for Lasers, Plasma and Radiation Physics, Magurele, Romania 5Research Institute for Solid State Physics and Optics, Budapest, Hungary 6Institut d'Optique, Campus de Polytechnique, RD12, Palaiseau Cedex, France 7Institute of Physics, University of Pecs, Hungary 8Institute of Optics and Quantum Electronics, Friedrich-Schiller Universitat, Jena, Germany 9Max-Planck Institutfur Quantenoptik, Garching, Germany '"Ludwig-Maximilians-Universitat, Munchen, Germany "LULI, Ecole Polytechnique, Route de Saclay, Palaiseau, France 12Max-Born-Institut, Berlin, Germany 13Department of Optics & Quantum Electronics, University of Szeged, Hungary "PALS, Institute of Physics, Prague, Czech Republic

Extreme Light Infrastructure (ELI), the first research facility hosting an exawatt class laser will be built with a joint international effort and form an integrated infrastructure comprised at last three branches: Attosecond Laser Science (in Szeged, Hungary) designed to make temporal investigation at the attosecond scale of electron dynamics in atoms, molecules, plasmas and solids. High Field Science will be mainly focused on particle acceleration and X-ray generation (in Prague, Czech Republic) as well as laser-based nuclear physics (in Magurele, Romania). The location of the fourth pillar devoted to Ultra High Field Science, which will explore laser-matter interaction up to the non linear QED limit including the investigation of vacuum structure and pair creation, will be decided in 2012. The primary objective of ELI project is to provide the worldwide scientific community a unique laser based research infrastucture, allowing them to investigate an unexplored domain of laser-matter interaction at the highest intensity level ever achieved, of the order reaching up to 1025 Wcm-2, which is more than three orders

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 23 c Abstracts - oral presentations ) of magnitude higher than today's state of the art. ELI will also be unique as it will produce a very broad range of ultrashort secondary sources devoted to various applications in physics, chemistry and biomedicine, including high energy photons, electrons, protons, neutrons, and muons, in the attosecond and possibly zeptosecond regimes, THz and X-ray, as well as gamma-ray beams. The research activities will be based on an incremental development of the laser sources with unprecedented peak power performance, from tens of petawatt (1015 W) up to a fraction of exawatt (1018 W). To surmount the four orders of magnitude increase of laser peak power from the state of the art as APOLLON, PFS, and VULCAN 10PW, several technical and scientific bottlenecks have to be addressed upon the design and construction of the machines. These are ranging from the production of high repetition rate high energy pump lasers, the challenge of coherent combination (including carrier envelope phase) of the high power laser beams over the temporal cleaning of the pulses up to fifteen orders of magnitude to the size and damage threshold of the compression gratings. At last, the current layout of the three ELI laser machines and the corresponding research infrastructures will be also presented.

Mo-10. The 10PW OPCPA Vulcan Project M. Galimberti. S. P. Blake, A. G. Boyle, O. Chekhlov, J. Collier, R. J. Clark, S. Hancock, R. Heathcote , C. Hernandez-Gomez, A. Lyachev, P. Matousek, I. O. Musgrave, D. Neely, P. A. Norreys, I. Ross, W. Shaikh, Y. Tang, T. B. Winstone, B. E. Wyborn Central Laser Facility, Science and Technology Facilities Council, Chilton, Didcot, Oxon. 0X11 OQX, United Kingdom

The aim of the 10PW project is to upgrade the existing Vulcan laser, located at the Central Laser Facility (CLF), to beyond the 10PW power level and provide focused intensities of greater than 1023 Wcnv2. To achieve these specifications we plan to generate pulses with energies of 300J and pulse duration less than 30fs using the technique of optical parametric chirped pulse amplification, OPCPA. The amplification is divided in three stages. In the first stage the laser pulse is generated and amplified up to |4 in the picosecond domain. Then the pulse is stretched to the nanosecond timescale and amplified up to the Joule level within a repetition rate of 2Hz. Using a novel amplification scheme in the first stage united to the dual CPA technique we will guarantee a high contrast pulse at the end of the system. The last stage is designed to increase the pulse energy up to 500J using a big single shot Nd:glass laser. The project has been divided in two Phases. The first was focused on the development of the frontend, i.e. the first two parts. In the Phase two, started few month ago, it is planned to design and realize the high energy part, the compression and the delivery to the target areas.

In this presentation we present the result of the front end united to the state of the art of the design, within all the issue that we have to overcome to achieve 10PW and, most important, to build a laser system usable to the community for experiments.

24 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 24 ) c Abstracts - oral presentations

Moll. Subatomic and frontier physics with ELI Beamlines: reality and dreams L. Drska Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 11519 Prague 1, Czech Republic

This contribution attempts to review some results of thinking about prospects for meaningful and procreative research by exploitation the potential of the unique laser technology to be available within the future ELI Beamlines Facility - an ultrashort-pulse, multi-petawatt, multi-beam, high-repetition-rate system [1], The presentation may be (hopefully) regarded as a specific contribution with the emphasis on two concrete areas to general ELI reports [2]. Two sets of potential studies will be discussed: (1) Realistic experiments. (2) "Dream" reserch..

The first set (maybe realizable in the first phase of the laboratory work) includes the following topics: (1) Laser-driven electronuclear processes. (2) Unconventional / NLTE fusion reactions. (3) Laser positron / antimatter physics [3], [4], Most detailed analysis will be presented for the subject (3). Some concrete themes planned for this part of the talk are: Challenges for laser positronium physics. Nuclear excitation in positron annihilation. Positrons and the laboratory astrophysics. Schemes of some experiments exploiting the ELI Bemlines possibilities will be displayed.

The second („dream") set to be outlined (under consideration as potential one for the second phase) should initiate a brainstorming discussion in these areas : (1) High-Z ion physics studies. (2) Exploring of high- gamma systems. (3) Search for hypothetic particles [5], Again, the highest attention will be paid to the topic (3). Key themes in this part: The search for hidden-sector lightweights. Challenges and oportunities in photon regeneration experiments. Potential of ELI Beamlines for the research in this area ?

The final section of the contribution will include some comments on technical issues related to the proposed research themes: (1) Novel targets and particle traps..(2) Diagnostics challenges and solutions. (3) Simulation / Evaluation problems. Some new approaches will be considered.

Acknowledgements This research has been supported by the Research Program No. 6840770022 of the Ministry of Education, Youth and Sports of the Czech Republic.

References [1] B. Rus , in Scientific Challenges on the Future ELI Beamlines Facility, Prague, April 26 - 27, 2010. http://www.eli-beams.eu/wp-content/uploads/2010/05/ELI Beamlines outline 2.pdf [2] ELI, Scientific Advisory Committee (SAC) Report / Grand Challenges Meeting Report (2009). http://www.extreme-light-infrastructure.eu/reports.php [3] H. Chen, S.C. Wilks, J.D. Bonlie et al., Physics of Plasmas 16, 122702 (2009). [4] Antimatter Creation Using Intense Lasers Workshop, Berkeley, CA, April 27 - 28, 2010. https://ilsa.llnl.gov/html/conferences/future/antimatter/antimatter.html [5] J. Jaeckel, A. Ringwald, CPT/10/18, DESY/10/016, IPPP/10/09. http://arxiv.org/PS cache/arxiv/pdf/1002/1002.0329vl.pdf

25 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations

Mo-12. Laser safety at high profile laser facilities K. Barat EH&S Division, Lawrence Berkeley National Laboratory (LBNL) - Berkeley, CA, USA *[email protected]

Laser safety has been an active concern of laser users since the invention of the laser. Formal standards were developed in the early 1970 s and still continue to be developed and refined. The goal of these standards is to give users guidance on the use of laser and consistent safety guidance and requirements for laser manufacturers. Laser safety in the typical research setting (government laboratory or university) is the greatest challenge to the laser user and laser safety officer. This is due to two factors. First, the very nature of research can put the user at risk; consider active manipulation of laser optics and beam paths, and user work with energized systems. Second, a laser safety culture that seems to accept laser injuries as part of the graduate student educational process. The fact is, laser safety at research settings, laboratories and universities still has long way to go. Major laser facilities have taken a more rigid and serious view of laser safety, its controls and procedures. Part of the rationale for this is that these facilities draw users from all around the world presenting the facility with a work force of users coming from a wide mix of laser safety cultures. Another factor is funding sources do not like bad publicity which can come from laser accidents and a poor safety record. The fact is that injuries, equipment damage and lost staff time slow down progress. Hence high profile/large laser projects need to adapt a higher safety regimen both from an engineering and administrative point of view. This presentation will discuss all these points and present examples. Acknowledgment This work has been supported by the University of California, Director, Office of Science References [1] K. Barat, "Laser Safety Management" CRC Press, 2006, [2] K. Barat, Laser Safety:Tools and Training CRC Press, 2009, [3] S. Gabay, "Laser Safety Management in a Research Institute, Paper 1201ILSC 2009 proceedings [4] G. Noojin, et at "A Practical Approach to Safe Use of Lasers in the Research Laboratory" paper 502, ILSC -2007 proceedings [ 5 ] J. Jones,et al "Improved Laser Safety Training Materials for University Students " paper #601, ILSC 2007 proceedings [6] L.Cridlin, "The Importance of Hands on Learning" paper 604, ILSC 2007 proceedings

Mo-13. Spectral coherent combination of ultrashort pulses D. Ursescu. R. Banici, L. Ionel, L. Rusen, S. Sandel, C. Blanaru National Institute for Lasers, Plasma and Radiation Physics, Magurele, Romania daniel. ursescu@inflpr. ro

The coherent beam combination was chosen in several laser systems, including ELI, as a solution to increase the final attainable intensity. However, the coherent beam combination it is also a difficult technique while it has to combine coherently in space and in time several beams amplified in different laser chains. That means in particular that the beams should be in phase in every point of the amplified beam so the spatial beam profiling techniques have to be mastered with high accuracy for all the combined beams. Here it is proposed an alternative coherent beam combination than the use of identical ultrashort pulses. The idea is to spectrally combine laser pulses with complementary spectra. Collinear and non-collinear approaches have been modelled. Ongoing experimental development, including the demonstration of the rephasing for two spectrally complementary ultrashort pulses will be presented. Acknowledgements The research leading to these results has received funding from the EC's Seventh Framework Programme (LASERLAB-EUROPE, grant agreement n° 228334).

26 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 26 c Abstracts - oral presentations )

Mo-14. Light Wave Synthesizer 20, a versatile front end for multi-PW few-cycle laser systems L. Veisz1, A. Buck12, K. Schmid1, J. Mikhailova1, T. Dou1, C. M. S. Sears1, R. Tautzu, D. Herrmann1'4, X. Gu1 and F. Krausz1'2 1 Max-Planck-Institutfur Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany 2 Ludwig-Maximilians-Universitat Munchen, Am Coulombwall 1, 85748 Garching, Germany 3 LSftir Photonik und Optoelektronik, LMU Munchen, Amalienstr. 54, 80799 Miinchen, Germany 4 LSfiir BioMolekulare Optik, LMU Munchen, Oettingenstr. 67, 80538 Munchen, Germany

The Light Wave Synthesizer 20 (LWS-20) is the first optical parametric chirped pulse amplifier (OPCPA) system with few-cycle pulse duration and 16 TW power worldwide[l]. In LWS-20 pulses from an ultra-broadband oscillator, producing -5.5 fs pulses with 80 MHz repetition rate, are split for optical synchronization and one part of them is wavelength shifted to 1064 nm to seed a commercial pump laser producing up to 1 J, 80 ps, 10 Hz pulses at 532 nm. The main part of the oscillator energy is amplified in a Femtopower Compact Pro 1 kHz laser to 900 pj energy and 25 fs duration. The broad seed spectrum for the optical parametric amplification (OPA) is generated by focusing into a tapered-hollow-core fibre filled with 2 bar neon. The cross-polarized wave generation technique[2] is implemented after the compression of this broadened bandwidth to increase the temporal contrast by 4 orders of magnitude. The pulses are stretched in a specially designed grism stretcher to about 25 ps and amplified in two consecutive noncollinear OPCPA stages based on BBO nonlinear optical crystals. The supported wavelength range of the OPA is from 700nm up to 980 nm, which corresponds to a Fourier limited pulse duration of sub-8 fs. The amplified pulses are compressed in a high transmission compressor containing bulk glasses of SF57 and quartz and by four chirped mirrors to about 8 fs. The pulse duration is optimized and tuned by an acousto-optical dispersive filter (DAZZLER). After the compressor a pulse energy of up to 130 mj is reached with >10 orders of magnitude contrast in the ± 25 ps temporal window and many orders of magnitude better outside this window. A Shack-Hartmann wavefront sensor and an adaptive mirror in a closed loop configuration are used to optimize the focusing properties of the laser to reach »1018 W/cm2 relativistic intensity on target. An upgrade is in progress to reach sub-5 fs pulse duration. Due to its practical spectral range, relative high energy, and good contrast the system is ideally suited as a front end for further amplification by Ti:Sa amplifiers into the muli-10-Joule range to reach ~10 fs pulse duration and multi-Petawatt peak powers. After the sub-5-fs upgrade a further amplification by consecutive OPCPA amplifiers offers to reach a quasi-single-cycle, multi-Joule, multi-Petawatt OPCPA system to extend the attosecond physics to relativistic laser-plasma environment[3].

Acknowledments

We thank the supply of the tapered-hollow-core fibre to M. Scharrer and P. S. J. Russell.

References [1] D. Herrmann et al., Opt. Lett. 34, 2459 (2009). [2] A. Jullien et al., Opt. Lett. 30, 920 (2005). [3] G. D. Tsakiris, et al., New J. Phys. 8,19 (2006).

27 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Mo-15. Generation of high-energy isolated attosecond pulses M. Lucchini. F. Ferrari, F. Calegari, C. Vozzi, S. Stagira, G. Sansone, M. Nisoli Dipartimento di Fisica, Politecnico di Milano and CNR-IFN, Piazza Leonardo da Vinci 32, 20133 Milano, Italy

Since the first experimental demonstration of the generation of isolated attosecond pulses, the attosecond technology has become an important branch of ultrafast science [1], So far, the reported applications of isolated attosecond pulses have been limited by the low photon flux of the available sources. We demonstrate a technique for the generation of isolated attosecond pulses with energy up to 2.1 nj. The key elements are: (i) the use of few-optical-cycle driving pulses with stable carrier-envelope phase (CEP), linear polarization and peak intensity beyond the saturation intensity of the gas used for HHG; and (ii) the optimization of the interaction geometry in terms of gas pressure, position and thickness of the gas cell.

•1 o 0 150 time delay (fs) Time (as) Fig. 1. (a) Portion of a FROG CRAB trace measured as a function of the temporal delay between the attosecond and the IR pulses; (b) reconstruction of the temporal intensity profile and phase of the attosecond pulses

We used 5-fs driving pulses with stable CEP to generate XUV radiation by HHG in a 2.5-mm-long cell filled with xenon at static pressure (2.5-3 torr) at a peak intensity /=(2.3±0.3) X1015 W/cm2. The XUV spectra display an evolution from a continuous behavior to a modulated one by changing the CEP value. The energy of the XUV pulses in the case of continuous spectra was 2.1 nj, after a 100-nm-thick aluminum filter used to block the fundamental radiation and the low order harmonics. We have also used argon, krypton and neon as generating media: also in such cases clear transition between modulated and continuous XUV spectra were observed upon changing the CEP of the driving pulses. We have measured the temporal characteristics of the attosecond pulses by using the FROG CRAB method [2], Figure la shows a portion of the FROGCRAB trace; in the reconstructed temporal intensity profile of the XUV pulses (see Fig.lb), the pulse duration was 155+5 as (the transform limit was ~120 as). The physical mechanism at the basis of this method is related to the ionization dynamics in the generating medium. We used a nonadiabatic three-dimensional numerical model [3], In agreement with experimental results, the calculated XUV spectra display an evolution from a continuous behavior to a modulated one by changing the CEP value. We have then calculated the propagation of the XUV beam from the gas cell to the target position by taking into account the effects of the toroidal mirror and of a 200-|im-diameter pinhole used for spatial filtering of the XUV radiation. With a proper choice of the CEP, isolated attosecond pulses are generated, with a constant pulse duration across the transverse profile of the beam, thus demonstrating the excellent spatial characteristics of the generated attosecond pulses. References [1] F. Krausz and M. Ivanov, Rev. Mod. Phys. 81, 163-234 (2009). [2] Y. Mairesse, F. Quere, Phys. Rev. A 71, 011401(R) (2005). [3] E. Priori et al, Phys. Rev. A 61, 63801 (2000).

28 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations

Mo-16. Deviations from the universal power law decay of harmonic spectra in ultra-relativistic laser-plasma interactions T.T.M. Boyd1, R. Ondarza-Rovira2 ' Centre for Theoretical Physics, University of Essex, Colchester C04 3SQ, UK 2Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Mexico 11801, D.F., Mexico

The influence of plasma effects on high harmonic spectra resulting from ultrarelativistic laser pulse interactions with over-dense plasma targets has been investigated by means of theoretical models supported by particle-in- cell (PIC) simulations. A potentially important effect of plasma waves driven by Brunei electrons is the weaken- ing of the so-called universal m~8'3 decay in the power emitted by high harmonics to spectra in which the decay index p = 8/3 is replaced by p = 5/3 or, less commonly, p = 4/3. The deviation from the universal spectrum is interpreted as a consequence of the extent to which emission at the plasma frequency and its harmonics con- 5 3 2 tribute to the spectrum. With strong plasma emission P(to) ~ to ' , top < a> <

Tu-1. The National Ignition Facility: the path to ignition and inertial fusion energy Erik Storm Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94450

The National Ignition Facility (NIF), the worlds largest and most energetic laser system built for studying inertial confinement fusion (ICF) and high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). NIF's 192 beams are capable of producing 1.8 MJ and 500 TW of ultraviolet light and are configured to create pressures as high as 100 GB, matter temperatures approaching 109 and densities over 1000 g/cmm3. With these capabilities, the NIF will enable exploring scientific problems in strategic defense, basic science and fusion energy. One of the early NIF campaigns is focusing on demonstrating laboratory-scale thermonuclear ignition and burn to produce net fusion energy gains of 10-20 with 1.2 to 1.4 MJ of 0.35 |im light. NIF ignition experiments began late in FY2009 as part of the National Ignition Campaign (NIC). Participants of NIC include LLNL, General Atomics, Los Alamos National Laboratory, Sandia National Laboratory, and the University of Rochester Laboratory for Energetics (LLE) as well as a variety of national and international collaborators. The results from these initial experiments show great promise for the relatively near-term achievement of ignition. Capsule implosion experiments at energies up to 1.2 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with low overall backscatter less than 10%. Cryogenic target capability and additional diagnostics are being installed in preparation for layered target deuterium-tritium implosions to be conducted later in 2010. The goal for NIC is to demonstrate a predictable fusion experimental platform by the end of 2012. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of Inertial Fusion Energy (IFE) and will focus

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 29 c Abstracts - oral presentations ) the world s attention on the possibility of IFE as a virtually inexhaustible, carbon free, energy option. This talk will summarize the capabilities of NIF, discuss NIF ignition, NIF's experimental program in HED science and the potential for laser-based fusion energy.

Tu-2. Shock ignition of high gain inertial fusion capsules G. Schurtz1, X. Ribeyre1, M. Lafon1, A. Casner2, E. Lebel1 ' Centre Lasers Intenses et Applications, UMR5107, Universite Bordeauxl, CNRS, CEA Universite Bordeauxl, 351 cours de la Liberation, 33405 Talence, France. [email protected] 2 CEA/DAM, Arpajon (France), [email protected]

Inertial Confinement Fusion relies on the compression of small amounts of an equimolar mix of Deuterium and Tritium (DT) up to volumic masses of several hundreds of g/cm3. Such high densities are obtained by means of the implosion of a spherical shell made of cryogenic DT fuel. In the conventional scheme a hot spot is formed in the central part of the pellet at the end of the implosion. If the pressure of this hot spot is large enough (several hundreds of Gbars), thermonuclear heating occurs with a characteristic time shorter than the hydrodynamic confinement time and the target self ignites. Since the central hot spot pressure results from the conversion of the shell kinetic energy into thermal energy, the threshold for the ignition of a given mass of DT is a direct function of the implosion velocity. Typical implosion velocities for central self ignition are of the order of 400 km/s. Such high velocities imply both a strong acceleration of the shell and the use of large aspect ratio shells in order to optimize the hydrodynamic efficiency of the implosion, at least in direct drive. These two features strongly enhance the risk of shell beak up at time of acceleration under the Rayleigh-Taylor instability. Furthermore the formation of the hot spot may itself be unstable, this reducing its effective mass. High compressions may be achieved at much lower velocities, thus reducing the energy budget and enhancing the implosion safety, but the corresponding fuel assembly requires an additional heating in order to reach ignition. This heating maybe obtained from a 70-100 kj laser pulse, delivered in 10-15 ps (Fast Ignition). An alternative idea is to boost up the central pressure of a target imploded at a sub-ignition velocity by means of a convergent strong shock launched at the end of the compression phase. This Shock Ignition (SI) concept has been suggested in 1983 by Scherbakov et al. [1]. More recently, R. Betti et al [2] developed the theoretical approach of SI, and Lafon et al [3] established its gain curves using an extension of the Rosen Lindl model. The efficiency of shock ignition comes from the fact that, unlike conventional central ignition, the final fuel assembly is not isobaric, i.e., the low density hot spot pressure significantly exceeds the pressure of the surrounding cold dense fuel. This high hot spot pressure is obtained from two pressure amplification stages : the first amplification mechanism is spherical convergence. A converging shock increases its strength as C09 where C is the shock convergence ratio. A second amplification stage occurs when the ignition shock collides with the outward directed shock that results from the shell stagnation at target centre. Under optimal matching conditions, shock collision produces a x 6 amplification of pressure. We discuss in the presentation the conditions for the obtention of optimal pressure amplification, at first by studying the ignition window in the space spanned by laser power and launching time, and secondly by modelling the relation ship between the laser intensity required for shock production and the implosion velocity. This latter study indicates a sensible safety trade off using a 250 km/s implosion velocity and a laser spike of ~5xl015 W/cm2 for the shock production. First kinetic calculations [4] and implosion experiments [5] indicate that laser plasma interaction in the regime of shock ignition may remain under control, provided that the SRS generated hot electrons energy stay below 80 keV. Shock Ignition has been proposed as the baseline of the HiPER [6] project and shock ignition experiments have been proposed on the National Ignition Facility with gains expected between 60 and 100 at laser energies below 500 kj.

30 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Acknowledgments

This work is partly supported by the Aquitaine Region Council.

References [1] Shcherbakov V. A, et al. Sov. Journal Plasma Physics, 1983 9 240. [2] Betti R. et al. Phys. Rev. Lett., 2007 98, 155001. [3] Lafon M. et al. Physics of Plasmas, 2010 17,052704. [4] Klimo O. et al. Plasma Phys. Control. Fusion, 2010 52, 055013. [5] Theobald W. et al. Physics of Plasmas, 2008 15, 056306. [6] Dunne M. et al. Nature 2006 2, 2.

Tu-3. The comeback of shock waves Shalom Eliezer12 and Jose Maria Martinez-Val1 'Institute of Nuclear Fusion, Polytechnic University of Madrid, Madrid. Spain 2Applied Physics Division, Soreq NRC, Yavne, Israel

The shock waves in laser plasma interaction have played an important role in the study of inertial fusion energy (IFE) since the 1970 s [1,2] (and perhaps earlier [3,4]). The interaction of laser (or any other high power beam) induced shock waves with matter was one of the foundations of the target design in IFE. Even the importance of shock wave collision was studied [5] and its importance forgotten. In due course the shock waves were taken as granted and became "second fiddle" in IFE scenario. At the forefront of past decade the "fast ignition" (with an extra multi-petawatt laser beam [6] or special impact target design [7]) received the leading role. Recently [8], the idea of combining the fast ignition with a shock wave was suggested. This is achieved by launching a shock wave during the final stage of the implosion in order to ignite the compressed fuel. In this scheme, like other fast ignition schemes, a significant reduction of the driver energy in comparison with standard IFE scenarios is required for the same high gain fusion. This paper contains a critical analysis of shock fast ignition. In particular, two of the problems will be discussed: (1) the high energetic electrons (higher than 100 keV associated with the last shock that can disturb the ignition and (2) the instability of the propagation of the igniting shock wave that might be a problem [9]. The shock fast-ignition scheme seems to be the easiest to implement (in the fast ignition models) and therefore the experimental proof of this scheme is of utmost importance. Some experiments for checking the feasibility of this idea will be suggested. Last but not least, a new variation of fast ignition shock will be proposed.

References [1] J. Nuckolls et al, Nature (London) 239, 139 (1972). [2] K. Breuckner and S. Jorna, Rev. Modern Phys. 46, 325 (1974). [3] R. E. Kidder, Nuclear Fusion 8, 3 (1968). [4] The pioneers in Inertial Confinement Nuclear Fusion: a Historical Approach by its Puioneers Eds. G. Velarde and N. Carpintero-Santamaria, Foxwell and Davies Pub., UK (2007). [5] S. Jackel et al, Phys. Fluids 26, 3138 (1983). [6] M. Tabak et al, Phys. Plasmas 1,1626 (1994). [7] M. Murakami et al, Nucl. Fusion 46, 99 (2006). [8] R. Betti et al, Phys. Rev. Lett., 98,155001 (2007) [9] S.Eliezer, J.M.Martinez-Val, C.Deutsch, Laser and Particle Beams, 13, 43 (1995).

31 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Tu-4. Ultrafast 25 keV backlighting for experiments on Z M. Geissel. M. Schollmeier, D. Headley, M. Kimmel, T. Pitts, P. Rambo, G. Robertson, A. Sefkow, J. Schwarz, C.S. Speas, and B. Atherton Sandia National Laboratories, Albuquerque, NM 87185, USA

Sandia is operating 'Z', a 26 MA z-pinch facility to conduct experiments in the field of high energy density physics [ 1 ]. For several years this facility has utilized Z-Beamlet, a kj/ns class laser system, to provide x-ray backlighting as a crucialdiagnostic[2].Duetothenatureoftheinteractionbetweennanosecondlaserpulseswithmatter,theefficiency of Z-Beamlet drops dramatically for x-ray energies beyond 6 keV, which does not longer suffice for a variety of experiments. In addition, several experiments require shorter pulses to freeze-frame fast processes.

To satisfy more demanding requirements of backlighting on Z, Sandia has built the Z-Petawatt laser, which can provide laser pulses of 500 fs length and up to 120 J (100TW target area) or up to 450 J (Z / Petawatt target area). While the new laser system had first successful experiments with stand-alone experiments such as novel intensity diagnostics [3] and proton acceleration [4], the main mission focuses on the generation of high energy

X-rays, such as tin Ka at 25 keV in ultra-short bursts. Achieving 25 keV radiographs with decent resolution and contrast required addressing multiple problems such as blocking of hot electrons, minimization of the source, development of suitable filters, and optimization of laser intensity. Due to the violent environment inside of Z, an additional very challenging task is finding massive debris and radiation protection measures without losing the functionality of the backlighting system. We will present the first experiments on 25 keV backlighting including an analysis of image quality, X-ray efficiency and redundantly engineered machine safety measures. Acknowledgement: Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000 References: [1] M.E. Cuneo et al.: Plasma Phys. Contr. Fusion, R1-R35 48 (2006) [2] D.B. Sinars et al.: Rev. Sci. Instrum. 75/10, 3673 (2004) [3] A. Link et al.: Rev. Sci. Intrum. 77, 10E723 (2006) [4] M. Schollmeier et al.: Phys. Rev. Lett. 101, 055004 (2008)

Tu-5. Near-field enhanced electron acceleration from dielectric nanospheres in intense few-cycle laser fields S. Zherebtsov1, Th. Fennel2, J. Plenge3, E. Antonsson3,1. Znakovskaya1, A. Wirth1, O. Herrwerth1, F. Sufimann', I. Ahmad1, S. Trushinjv. Pervak4, S. Karschl4, M.J.J. Vrakking5-6, B. Langer3, C. GraP, M. Stockman1'7, F. Krausz1'4, E. Riihl3, M.F. Kling1 'Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching, Germany 'Institute of Physics, University Rostock, Universitaetsplatz 3, 18051 Rostock, Germany institute of Chemistry and Biochemistry, Free University of Berlin, Takustr. 3, 14195 Berlin, Germany 4Physics Department, Ludwig-Maximilian University, Am Coulombwall 1, 85748 Garching Germany 5Max Born Institute, Max-Born Strasse 2A, 12489 Berlin, Germany 6FOM Institute for Atomic and Molecular Physics, Science Park 113, 1098 XG Amsterdam, The Netherlands 7Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, USA .

The interaction of nanostructured materials with few-cycle laser light has attracted significant attention lately [1-3]. This interest is driven by both the quest for fundamental insight into the real-time dynamics of many- electron systems and a wide range of far-reaching applications, such as, e.g. ultrafast computation and information storage on the nanoscale and the generation of XUV frequency combs.

32 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

We investigated the above-threshold electron emission from isolated Si02 nanoparticles in waveform controlled few-cycle laser fields at intensities close to the tunneling regime [4]. The enhancement of the electron acceleration from the silica nanoparticles was explored as a function of the particle size (ranging from 50 to 147 nm) and the laser peak intensity (1 - 4-10" W/cm2). Obtained cut-off values in the kinetic energy spectra are displayed in Fig. 1. The cut-off values show a linear dependence with intensity within the studied intensity range, with the average cut-off energy being 53 U , indicated by the black line. Quasi-classical simulations of the emission process reveal that electron rescattering in the locally enhanced near-field of the particle is responsible for the large energy gain. The observed near-field enhancement offers promising new routes for pushing the limits of strong-field phenomena relying on electron rescattering, such as, high-harmonic generation and molecular imaging.

laser intensity (1013W/cm2)

Fig. 1 Dependence of the cut-offs in the electron emission spectra from Si02 nanoparticles on laser intensity. Nanoparticles of different sizes are represented by different symbols as indicated in the legend.

References [1] P. Vasa et al., Laser & Phot. Rev. 3,483 (2009) [2] M.I. Stockman, New J. Phys. 10, 025031 (2008) [3] S. Kim et al., Nature 453, 757 (2008) [4] S. Zherebtsov et al., in preparation.

Tu-6. QED studies using high-power lasers Mattias Marklund Department of Physics, Umea University, SE-901 87 Umea Sweden E-mail: [email protected]

The event of extreme lasers, for which intensities above 1022 W/cm2 will be reached on a routine basis, will give us opportunities to probe new aspects of quantum electrodynamics. In particular, the non-trivial properties of the quantum vacuum can be investigated as we reach previously unattainable laser intensities. Effects such as vacuum birefringence and pair production in strong fields could thus be probed. The prospects of obtaining new insights regarding the non-perturbative structure of quantum field theories shows that the next generation laser facilities can be an important tool for fundamental physical studies. Here we aim at giving a brief overview of such aspects of high-power laser physics.

33 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations

Tu-7. Ion deceleration in interpenetrating plasma jets Q. Renner1. E. Dalimier2, E. Krousky1, O. Larroche3, R. Liska4 'Institute of Physics, v.v.i., Academy of Sciences Czech Rep., Na Slovance 2,182 21 Prague, Czech Republic 2Universite Pierre et Marie Curie UPMC, LULI, UMR 7605, Paris, France 3CEA DIF, Bruyeres le Chatel, 91297 Arpajon Cedex, France 4Czech Technical University in Prague, FNSPE, Brehovd 7, 115 19 Prague, Czech Republic

Inertial and magnetic confinement fusion schemes involve collisions of high-temperature plasma jets and their interaction with solid surfaces (the so-called plasma-wall interaction, PWI). A fundamental understanding of the PWI effects requires a detailed characterization of the transient collisional phenomena occurring in the interaction region. In this paper we discuss a PWI experiment with double-foil Al/Mg targets fielded at the PALS laser system.

An energetic plasma jet was created at the rear (non-irradiated) side of the 0.8-pm-thick Al foil exploded by the main laser beam (50-200 J, 0.44/1.315 pm, 0.25-0.3 ns,

The interaction scenario was numerically modeled by two concerted codes, namely, i) the Prague Arbitrary Lagrangian Eulerian 2-D code PALE, which solves the Lagrangian mesh distortions by smoothing and con- servative remapping of conserved quantities, and ii) the multispecies 1.5-D code MULTIF which models the hydrodynamics of an arbitrary number of interpenetrating ion species in a single space dimension while assuming self-similar plasma expansion in the other directions, and taking into account detailed Coulombian collisional processes. PALE was used to model two counter-streaming Al/Mg plasma plumes until the beginning of their interaction, and the resulting plasma state was then used as an initial condition for the simulation of the subsequent plasma interpenetration by MULTIF.

The fine structure in the Al ion velocity profile discovered near the Mg wall is discussed with respect to the numerical description of the interpenetration and stagnation of the counter-propagating plasmas, in particular in terms of the trapping and thermalization of the Al plasma jet close to the Mg target.

To conclude, a combination of high-resolution x-ray spectroscopy with advanced plasma simulations contributes to a development of new diagnostics for investigation of PWI effects. The reported results provide novel information on interaction of high-temperature plasma jets with walls and more specifically, on the ions deceleration in the near-wall plasma region.

Acknowledgments The help of M. Smi'd in experimental data reconstruction is acknowledged. This research was supported by the Czech Science Foundation Grant P205/10/0814, the CNRS PICS project No. 4343 and the Czech Ministry of Education, Youth, and Sports projects No. MSM 6840770022 and LC528.

34 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 34 c Abstracts - oral presentations )

Tu-8. Interaction physics in the context of ICFwith the LIL facility C. Labaune1. S. Depierreux2, V. T. Tikhonchuk3, D. T. Michel1-2, C. Stenz3, N. G. Borisenko4, P. Nicolai3, M. Grech35, G. Riazuelo2, S. Hiiller6^D. Pesme6, P. Loiseau2, P.E. Masson-Laborde2, M. Casanova2, C. Riconda1, S. Weber3, S. Darbon2, R. Wrobel2, E. Alozy2, W. Nazarov*, J. Limpouch8, A. Casner2, C. Meyer9, P. Romary9, G. Thiell9 lLaboratoire pour I'Utilisation des Lasers Intenses, Ecole Polytechnique, Palaiseau, France 2CEA, DAM, DIF, F-91297 Arpajon, France 3Centre Lasers Intenses et Applications, Universite Bordeaux 1, CEA, CNRS, Talence, France 4P. N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia 5Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany 6Centre de Physique Theorique, Ecole Polytechnique, 91128 Palaiseau cedex, France 7University of St. Andrews, Fife KY16 9ST, Scotland, UK 8FNSPE, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic 9CEA,DAM, CESTA, F- 33114 Le Barp, France [email protected]

Laser-plasma interaction physics is one of the main challenges of Inertial Confinement Fusion. Experiments in large-scale, high temperature, plasmas are needed to understand the physics of parametric instabilities, mainly the stimulated Brillouin and Raman scattering and filamentation. Experimental results obtained with well- defined interaction conditions are needed to test the numerical simulations still under development and to improve the target design. To be carried out with long length and high temperature plasmas, the experiments require multikilojoule laser beams, a careful choice of targets and sophisticated diagnostics. The LIL (Ligne d'lntegration Laser) facility has been used with foam layer targets to study interaction physics in underdense plasma, in the millimeter scale, at temperature around 2 keV. The LIL facility delivers 12 kj of 3co light in pulses of 2.7 ns in a quadruplet. Low-density foams (3 to 10 mg/cc) with lengths in the range [300 |im,l mm] and very small microstructures (~|im) have been used. The plasma parameters, electron density, velocity, temperature profiles, were obtained from hydrodynamics simulations with the code CHIC and HERA. The numerical results were compared with the experimental measurements of longitudinal X-ray images at different times, the temporal evolution of the transmitted light through the foam, and the overall energy balance. Results will be presented on the beam propagation through the foam, plasma induced smoothing, the reduction of the imprint and stimulated Brillouin and Raman scattering. The interpretation of these results is achieved by means of various interaction codes, PARAX, HARMONY and HERA.

Tu-9. An overview of IFE-related technologies developed in Russia E.R.Koresheva, I.V.Aleksandrova P.N.Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia

In Russia, at Lebedev Physical Institute of Russian Academy of Sciences (LPI), the issues of IFE target fabrication are focusing on methods that will scale to a high rep-rate and cost-effective target production. To realize the goal, an approach based on using free-standing targets (FST) at each production step has been developed at LPI.

In this report we discuss the main results achieved at LPI in the area of IFE-related technologies: 1. It has been shown (theoretically and experimentally) that the fuel layer structure is of crucial importance for the development of IFE injection scenario. In optimal case, the fuel layer should be in an ultra-fine state. 2. Experimentally, the FST technologies developed at LPI allow forming the cryogenic layers in an ultra-fine state. Using high-melting additives in the range of 3-to-20% stabilizes the meta-stable ultra-fine fuel layers. That

35 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations means that the FST technology is promising for the formation of ultra-fine cryogenic layers from DT-mixture. Tritium here stands as a high-melting additive relative to deuterium. 3. Program "Multiple target protection methods" is under way. Among they are: - Target materials. They must satisfy a wide range of required and desirable characteristics. Optimal micro- structural design and materials selection allow one to obtain chemical, physical and mechanical characteristics for specific applications. - Outer reflective metal coating. This has been experimented by depositing the outer reflective layer of Pt/Pd

(200 A thick) onto the polystyrene shell (1.5 mm-diam.) and filling it with D2 fuel (50 pm-thick layer) having 3% additive of Ne. Then, a solid layer is formed inside the shell by the FST layering method. - Outer protective cryogenic coating (solid Xe, Ne or DJ. Using the piezo-vibrator (i.e. R&B cell made at LPI) the outer cryogenic layers from solid 02 have been fabricated onto the polystyrene shells. These proof-of-principle experiments showed the possibility to form outer protective cryogenic layers. - Protective cover (shroud). The target injection scenario has been developed including co-injection of a special protective cover (shroud from solid Xe, Ne or D2) ahead of the target that forms a wake area in the fill gas to avoid convective heating. 4. A concept of target factory based on PST technologies have been proposed at LPI and then examined in 7 different projects. The concept aims to demonstrate large benefits of using free-standing targets for realization of a production scheme "covering the shells with an outer protective layer - shells filling with fuel - fuel layering inside a batch of moving free-standing shells - rep-rate assembly of target-&-sabot units - target injecting". In the process, the target interface issues are of critical importance. 5. A prototypical target factory was accomplished at LPI with the demonstration of filling (up to 1000 atm), layering (up to 100 pm-thick layers) and injection of millimeter size free-standing targets. The repetition rate is about 0.1 Hz 6. Research has shown that the FST technologies are suitable not only for spherical cryogenic targets, but also for cylindrical ones (hohlraum targets for laser and heavy-ion drivers, cryogenic cylindrical targets for LAPLAS experiments on the FAIR facility etc.) 7. The created science & technology base is currently used at LPI for development of the FST- layering module for a high rep-rate production of cryogenic spherical shock ignition targets of a HiPER-class (0-2 mm, W = 211 pm; £,-200 kj, v > 1 Hz). The aim of these targets is to demonstrate the feasibility of laser driven fusion for IFE reactor.

Tu-10. Anomalous behavior of femtosecond-laser excited solid A. NgH T. Ao1, G. Collins2, A. Ellis2, M. Foord2, S. Hansen2, D. Hanson1, B. Isaacs2,1. Koslow1, E. Lee1, xj Ogitsu2, Y. Ping2, D. Prendergast3, D. Price2, E. Schwegler2, V. Sonnad2, P. Springer2, P. Sterne2, H. Tam1, K. Widmann2, and B. Wilson2 'University of British Columbia, Canada 2Lawrence Livermore National Laboratory, U.S.A. 3Lawrence Berkeley National Laboratory, U.S.A.

Femtosecond-laser excitation is a key means of creating well-defined, uniform states of Warm Dense Matter/ High Energy Density Matter through isochoric heating of a solid. The process is generally thought to be strict forward. Laser absorption by electrons leads to electron heating. Thermalization of the heated electrons occurs in femtosecond time scales, followed by heating of the lattice via electron-phonon coupling. Isochoric heating condition is maintained only briefly until the lattice reaches its melting temperature and disassembles. However, a series of systematic studies of femtosecond-laser excited gold has revealed some highly unusual behavior. This talk is a review of our experiments and accompanying observations of a superheated warm dense solid, lower than expected conduction electron density, and non-equilibrium electron density of states. Comparisons will be made with other theoretical and experimental results. Our findings suggest the need

36 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 36 c Abstracts - oral presentations )

for detailed understanding of the unique characteristics of Warm Dense Matter/High Energy Density Matter produced by ultrafast excitation. This applies to isochoric heating induced by not only lasers but likely also X-ray and energetic charged particles.

Tu-11. Evolution model of turbulent mixing under laser thermonuclear target compression V. Rozanov1. N.Zmitrenko2, R.Yakhin1, P.Kuchugov1 ' P.N.Lebedev Physical Institute ofRAS, Moscow, Russia rozanov@sci. lebedev. ru 2 Institute of Applied Mathematics ofRAS,, Moscow, Russia

An evolutionary model of hydrodynamic instabilities and turbulent mixing is based on a similarity of the scenarios of the development of instabilities of different scale. The perturbations pass a linear (exponential) stage, and then enter a nonlinear stage, when the growth rate essentially drops. The nonlinear stage (and the criteria of its beginning) are defined by a competition of the primary RTI (Rayleigh-Taylor instability) or RMI (Richtmyer-Meshkov instability) and the secondary KHI (Kelvin-Helmholtz instability) [1,2]. The similarity in the development of different scale instabilities has been repeatedly observed in the experiments and direct numerical simulations. This allows one to propose analytical ratios, which define the a coefficient in a well- 2 known ratio Lmjs = agAt . The results strongly depend on the initial perturbation spectrum. On the same basis one can propose an analytical model, which describes the mixing zone width and its development making use of certain initial conditions of laser thermonuclear target compression [3]. Here the mixing takes place under a finite time of compression, and the evolutionary model holds greater validity. Direct numerical simulations confirm the validity of the proposed models. One of the important issues is to establish the relationship between the mixing zone parameters and the neutron yield degradation due to the mixing of DT-fuel and shell matter. The results depend on the target design and size, and the laser pulse energy. The paper presents the results from 2D simulations of the compression and neutron yield for the target of the Iskra-5 facility scale (an iodine laser, 2a>, X=0.66 [im, the pulse energy, ~2 kj, the pulse duration =0.7 ns) [4]. The simulations have been performed for various initial conditions and different variants of neutron yield degradation under the mixing process. References [1], V.B.Rozanov, N.V.Zmitrenko. Preprint of P.N.Lebedev Physical Institute ofRAS, N16, Moscow, 1992. [2]. N.V.Zmitrenko, N.G.Proncheva, V.B.Rozanov. Preprint of P.N.Lebedev Physical Institute of RAS, N65, 1997. [3], N.V.Zmitrenko, N.G.Proncheva, V.B.Rozanov, R.A.Yakhin. Quantun Electronics, 2007, 37(8), pp.784-791. [4], V.B.Rozanov etal.JETP, 2010.

TU-12. Exploring warm dense matter by innovative XUV and X-ray plasma spectroscopy U. Zastrau. I. Uschmann, E. Forster, et al. X-ray Optics Group, Institute for Optics and Quantum Electronics, FSU Jena

We presented work aims for the creation and characterization of defined states of Warm Dense Matter (WDM). This is a highly transient non-equilibrium state at the transition of cold condensed matter to hot plasmas. In the experiments presented, it is formed by the interaction of high-intensity, short-pulse sources with solid matter and investigated by plasma spectroscopy with high-energy photons, e.g. in the XUV or X-ray regime. We tightly focus high-power optical laser radiation (100TW Laser, LULI, France) onto titanium foils. A toroidally bent crystal spectrometer observes the Ti Ka-photons emitted by this plasma with one- dimensional spatial resolution. Sophisticated analysis reveals radially resolved temperature distributions of the

37 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations D

plasma at temperatures up to 30 eV, in a central region significantly larger than the laser focal spot [1]. Further, we investigate the formation of WDM by photo-ionizing aluminum samples with high-intensity XUV-pulses (92 eV photon energy) from the free-electron-laser FLASH (Germany). The plasma self-emission, surveyed by a XUV grating spectrometer [2], reveals the fundamental plasma parameters [3,4]. We hence study the excitation and relaxation of the generated state by analysing continuum radiation, ion-line ratios and fluorescence from the heated conduction band. At highest XUV intensities of up to 1016 W/cm2, we present the first observation of saturable absorption in the soft X-ray regime by turning an aluminium foil transparent [5]. References [1] U. Zastrau, P. Audebert, I. Uschmann, E. Forster, et al.,Phys. Rev E 81, 026406 (2010) [2] R. R. Faustlin, U. Zastrau, et al., Journal of Instrumentation 5 P02004 (2010) [3] U. Zastrau, C. Fortmann, et al., Phys. Rev. E 78, 066406 (2008) [4] S. Toleikis, et al., High Energy Density Physics 6 (2010), 15-20 [5] B. Nagler, U. Zastrau, et al., Nature Physics 5 (2009), 693 - 696

Tu-13. Simulation of ultra-intense laser-matter interaction: The onset of cascading Hartmut Ruhl and Nina Elkina Computational and Plasma Physics, Ludwig-Maximilians-University, Theresienstrasse 37, 80333 Munich, Germany

With the advent of ELI super-intense laser fields will become available that may interact strongly with the quantum vacuum. The most prominent signal to be expected from vacuum in the presence of ultra-intense laser fields are cascades of electrons, positrons and photons starting off from initial seeds that can be either electrons, positrons or photons [ 1 ]. Cascading strongly depends on a quantum efficiency parameter that essentially represents the magnitude of the external laser field in terms of the Schwinger field in the rest frame of the charged particle. Since the latter can be smaller than unity for efficient hard photon emission cascading can be observed at laser fields far below the Schwinger limit. The presentation will show simulations about the onset of cascading from an initial electron as well as photon seed in the presence of two circularly polarized counter-propagating laser pulses. The related growth rates are presented. Details of the simulations will be given. Acknowledgements This work has been funded by the Munich Centre of Advanced Photonics. References [1] A. I. Nikishov and V. I. Ritus, Quantum Processes in the field of a plane electromagnetic wave and in a constant field, SOVIET PHYSICS JETP, 19 (1964).

38 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 38 c Abstracts - oral presentations )

We-l. Ion beams - advances in spectral and efficiency control D Neelv"1, D C Carroll2, P S Foster13, M. Giinther4, K. Harres4, S. Kar3, K. Lancaster1, K. Markey1, P. McKenna2, F. Nurnberg^M.N. Quinn3, M. Roth4, M. Schollmeier4 and M ZepP 1 Central Laser Facility, Rutherford Appleton Laboratory, STFC, Didcot, Oxon, UK 2SUPA, Department of Physics, University ofStrathclyde, Glasgow, UK department of Physics and Astronomy, Queens University Belfast, Belfast, UK 4GSI, University of Darmstadt, Germany

As the physical processes controlling the transfer of energy between the driving laser, the intermediate electrons and the ions becomes more fully understood, new methods for controlling the accelerated ion beam become accessible. Here, two optically based techniques will be examined which have the ability to enhance the production efficiency and modify the spectral content of the beam. In an experiment conducted using the Vulcan Ndiglass laser, pulses of 0.7 ps were directed onto thin Al foils. The spectral content of the ion beam produced from the Al targets was monitored as the laser focal spot size on target was increased from 5 microns to 300 microns. As the spot size is increased the intensity reduces and it is possible to use thinner targets. Generally, the flux of ions increases as the foil thickness decreases until a critical minimum thickness is reached for a given irradiance. This result gives a clear demonstration of the effect of refluxing on the ion beam spectrum and maximum energy. Results showing the scaling and efficiency of this technique will be reviewed. In a second experiment, a dual pulse drive was used to modify the spectral content of the ion beam. Results showing the sensitivity of this technique to the relative ratio and timing between the two drive pulses will be presented.

We-2. Inertial Fusion Energy with Krypton Fluoride Lasers lohn D. Sethian Naval Research Laboratory, Washington DC [email protected]

We are developing the science and technologies needed for a practical fusion energy source using high energy krypton fluoride (KrF) lasers. The physics basis for this work is a family of simulations that exploit the unique advantages of KrF lasers. KrF lasers provide uniform enough laser light to illuminate the capsule directly, greatly improving the laser-target coupling efficiency, as well as simplifying the target design. KrFs shorter wavelength allows higher ablation pressures and helps suppress laser-plasma instabilities. These advantages are being demonstrated on the NRL Nike KrF laser facility. A particularly promising approach is shock ignition, in which a high intensity laser pulse drives an intense shock at peak compression. Simulations with experimentally benchmarked codes predict a 1 MJ KrF laser can produce 200 MJ of pure fusion energy. We have similarly advanced the laser technology. We have developed a KrF laser, using technologies that scale to a reactor beamline, that fires 5 times per second for long duration runs and is projected be efficient enough for a reactor. The science and the technology for the key components are developed at the same time as part of a coherent system. A multi-institutional team from industry, national labs, and universities has developed credible solutions for these components. This includes methods to fabricate the spherical pellets on mass production basis, a means to repetitively inject the capsules into the chamber and precisely hit them with the laser, scaled tests to develop the laser optics, and designs for the reaction vessel. Based on these advances NRL and its collaborators have formulated a three stage plan that could lead to practical fusion energy on a much faster time scale than currently believed. Stage I develops full scale components: a laser beam line, target factory and injector, and chamber technologies. Stage II is the Fusion Test Facility (FTF).

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 39 c Abstracts - oral presentations )

Simulations show a 500 kj, 5 Hz KrF laser and could produce more than 100 MW of fusion power. It would optimize the target physics and demonstrate integration as well as be used to validate materials and sub modules in a fusion environment. It could be operating by 2025. Stage III would be a demonstration power plant based on the FTF, and would probably be led by industry. Acknowledgements: The work here was performed by over 60 researchers in the NRL Laser Plasma Branch and the US High Average Power Laser Program. Work supported by US Office of Naval Research and the US Department of Energy.

We-3. Radiation resistance of transmissive optics for IFE reactor chamber and KrF laser driver V. D. Zvorvkin11. A.S. Alimov2, S. V. Arlantsev3, B. S. Ishkhanov2, A. O. Levchenko1, N. N. Mogilenetz4, V. F. Oreshkin1, A. P. Sergeev1, P.B. Sergeev1, V. F. Shtanko5, V. I. Shvedunov2 and N. N. Ustinovskii1 'P.N. Lebedev Physical Institute ofRAS, Leninsky Prospect 53, Moscow, 119991 Russia 2 D.V. Skobel'tsyn Institute of Nuclear Physics, Moscow State University,Vorob'evy gory 1, Moscow, 119992 Russia 3 V.K. Orlov OKB "Granat", Volokolamskoe Shosse 95, Moscow, 125424 Russia 4 National Research Nuclear University „MEPhI", Kashirskoe Shosse 31, Moscow, 115409 Russia 5 Tomsk Polytechnic University, Tomsk, Prospect Lenina 30, 634050 Russia

Laser driver of the Inertial Fusion Energy (IFE) power plant should operate at repetition rate of 5-10 Hz uninterruptedly for two years with pulse energy ~1 MJ and overall efficiency -7%, producing totally ~ 3* 10s pulses [1]. Among present candidates only DPSSL and e-beam-pumped KrF lasers can satisfy these severe conditions [2]. High radiation stability is required for laser and reactor chamber optics suffering from different kinds of ionizing radiation. For instance, cumulative absorbed doses ~1 MGy of hard X-rays in KrF laser or target chamber windows during operation run was shown to reduce their transmittance significantly [3]. We performed comprehensive studies of transient and residual absorption induced in VUV, UV and visible ranges in fused silica glasses Corning 7980, Russian KU-1 and KS-4V, crystals CaF2, MgF2 and A1203, being irradiated at several pulsed facilities by 280-keV e-beam, high-intensity UV laser light, and bremsstrahlung X-rays [4]. Optics response to hard X-ray photons (hv - 400 keV), which are usually generated during e-beam pumping of KrF amplifiers, was measured at a linac-based powerful quasi-CW X-ray source. It allowed X-ray dose rate -40 Gy/s and amassed doses absorbed in samples volume -1 MGy [3]. Another test bench rep-rate X-ray source based on high-voltage glow discharge produced average irradiation intensity 2-3 mW/cm2 in a 50- Hz train of -1 -ps pulses with photon energy of hv = 6-20 keV. Being absorbed in a thin surface layer it provides dose rates up to 5 Gy/s. Just in the same soft X-ray range there is the most release of an imploding fusion target. Also, at hv -2 keV characteristic K lines of Ar and Kr (contained in a working gas) make significant contribution into X-ray spectrum illuminating KrF laser windows. The obtained results show that transient absorption at both 248-nm (KrF) and 353-nm (3co DPSSL) wavelengths hardly affect on optics transmission, while residual absorption results in rather high losses especially for UV laser light. Annealing at elevated temperatures should be anticipated, which will reduce color centers formation and keep the initial optics transmission. Acknowledgments This work was supported by Russian Foundation for Basic Research (grant No. 08-02-01331) and by KrF IFE program of the US Naval Research Laboratory. References [1] I.N. Sviatoslavsky, M.E. Sawan, R.R. Peterson, et al., Fusion Technology, 21, 1470 (1992). [2] J.D. Sethian, M. Friedman, R.H. Lehmberg, et al., Nucl. Fusion, 43,1693, 2003. [3] A.S. Alimov, B.S. Ishkhanov, V.I. Shvedunov, et al., Moscow University Physics Bulletin, 65, 111 (2010). [4] V.D. Zvorykin, S.V. Arlantsev, R.V. Gaynutdinov, etal, J. of Phys: Conference Series, 112, 032055 (2008).

40 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

WeSl-l. Beam shaping of laser-generated particles with conventional accelerator devices P. Antici1". C. Benedetti4, E. Chiadroni2, M. Migliorati23, A. Mostacci23, C. Ronsivalle5, L. Picardi5, L. Palumbo23 " ILE - ENSTA - Ecole Polytechnique - CNRS - logs - UP Sud, Batterie de I'Yvette, 91761 Palaiseau, France 2> Istituto Nazionale di Fisica Nucleare, Via E. Fermi, 40, 00044 Frascati, Italy 3> Dipartimento di Energetica, Universita «Sapienza», Via Scarpa 14, 00161 Roma, Italy 4> Lawrence Berkeley National Lab, Berkeley, CA 94720, USA 51ENEA C.R. Frascati, Frascati, Italy [email protected]

Particle beams produced by laser-plasma interaction are arousing a strong interest in the last decade due to their attracting characteristics in terms of energy, particle number and emittance. In particular, the high accelerating gradient, almost 1000 times stronger than in conventional accelerators, makes them a very interesting alternative to conventional LINACs or cyclotrons, reducing potentially its size and costs. However, currently the laser-generated beam parameters are not adequate for replacing traditional accelerator facilities based on RF technology, and are therefore not suitable for the manifold applications that particle accelerator can be used for. In this paper we present different ways to shape laser-generated particles, in particular protons and electrons, using conventional RF devices. The study related to capture, shape and transport of those beams, as well as their use as injector to a Free Electron Laser, has been done by means of different tracking codes, well established in the accelerator community, and focuses on laser-generated particles obtained nowadays by conventional multi hundred TW laser systems. This allows identifying which are the crucial parameters of those beams and consequently permits improving the beam characteristics for generating reliable and controllable particles sources such as could be obtained by higher power laser systems, such as the Extreme Light Infrastructure.

WeSl-2. Ion acceleration via interaction of intense laser pulse with cluster-gas target Yuji Fukuda Kansai Photon Science Institute (KPSI) and Photo-Medical Research Center (PMRC), Japan Atomic Energy Agency (JAEA), Japan

The recent development of ultrashort-pulse, high peak power laser systems enables us to investigate high field science under extreme conditions [I]. Ion acceleration with intense laser pulses has been one of the most active areas of research in high field science during the last several years, due to the broad range of applications including cancer therapy [2,3], One of the important aims is the enhancement of the ion energy to the range usable in cancer therapy. We present a new approach where high energy ions are generated from the irradiation of a cluster-gas target by a compact ultrashort pulse laser [4], With this approach, we have demonstrated efficient generation of high energy ions with energies up to 10-20 MeV per nucleon and with a small full-angle divergence of 3.4' by irradiating the replenishable cluster-gas target with 40-fs laser pulses of only 150 mj energy at 1 Hz repetition rate. This corresponds to approximately tenfold improvement of the accelerated ion energy compared to previous experiments with solid targets. It is inferred from 2D-PIC simulations that the high energy ions are generated due to formation of a strong dipole vortex structure. The demonstrated method has a potential to construct compact and high repetition rate ion sources for hadron therapy and other applications. The latest experimental results of ion acceleration using the cluster-gas target with 40-fs laser pulses of 1-J energy will be also presented in the presentation. References: [1] G.A. Mourou et al., Rev. Mod. Phys. 78, 309 (2006). [2] S. V. Bulanov et al., Plasma Phys. Rep. 28, 453 (2002). [3] T. Tajima, D. Habs, and X. Yan, Rev. Accel. Sci. Tech. 2, 201 (2009). [4] Y. Fukuda et al., Phys. Rev. Lett. 103, 165002 (2009).

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 41 c Abstracts - oral presentations )

WeSl-3. Laser driven ion acceleration using isolated, mass-limited spheres T. Paasch-Colberg1*2. T. Sokollik1'3, K. Gorling1, M. Schnuerer', U. Eichmann1, S. Steinke1, P.V. Nickles4, A. Andreev1'5 and W. Sandner1 1 Max Born Institute, Max-Born-Str. 2a, 12489 Berlin, Germany 2 Max Planck Institute of Quantum Optics, Hans-Kopfermann-Str. 1, 85748 Garching, Germany 3 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, United States 4 GIST, Gwangju 500-712, Republic of Korea 5 Vavilov State Optical Institute, St. Petersburg, Russia

We present experiments on laser driven ion acceleration that were carried out at the Max Born Institute using fully isolated, mass-limited spheres with a diameter down to 8 pm for the first time. Recently, the acceleration process from laser irradiated water droplets has been studied using proton imaging [ 1 ]. The accelerated ion beams showed unique attributes like quasi-monoenergetic spectra [2], Based on the isolation and mass-limitation several phenomena have been predicted regarding the emission of ions. Due to the spherical geometry the ions are usually emitted over the full solid angle. Theoretical studies predict higher proton energies compared to foil targets of similar thickness [3]. However, in the experiments a directional ion emission has been observed and the predicted energy increase did not occur. The proton imaging experiments revealed that an ambient plasma (ionized water vapor) plays an important role for the whole processes of charge transfer which affects the fields being responsible for the ion acceleration [4], We realized a novel approach to investigate the mechanism of laser driven ion acceleration from fully isolated glass spheres. To provide fully isolated targets, without the influences of mountings, neighboring targets or ambient plasma, we set up a linear Paul trap. We measured quasi-monoenergetic ion spectra emerging from different spheres with a diameter between 30 and 8 pm. 2D-PIC and hydro-code simulations were used to show that the pre-plasma at both the front and rear sides of the target crucially affect the efficiency of the ion acceleration. The mechanism of the pre-plasma flowing around mass-limited targets has not been recognized so far for laser driven ion acceleration. Our models indicate that this effect causes the observed limitation of the ion-beam energy in former as well as in our experiments. In addition, recent experiments that were performed at the Max Planck Institute of Quantum Optics are presented briefly. Here, we aim for lightwave control of collective electron motion in nanoscaled dielectrics and semiconductors using intense, CEP-stabilized, near single-cycle NIR laser pulses.

Acknowledgements: This work was partly supported by DFG-Sonderforschungsbereich Transregio TR18, GRK 1203 and EU Grant (Marie Curie) (No. PIIF-GA-2008-221727).

References: [1] T. Sokollik et al., Phys. Rev. Lett. 103, 135003 (2009). [2] S. Ter-Avetisyan et al., Phys. Rev. Lett. 96,145006 (2006). [3] J. Psikal et al., Czechoslovak Journal of Physics 56, B515 (2006). [4] T. Sokollik et al., AIP 1153, 364 (2009).

42 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations

WeSl-4. High energy ion generation via magnetic vortex acceleration Tatsufumi Nakamura. Sergei V. Bulanov, Timur Zh. Esirkepov, Masaki Kando Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-6 Umemidai, Kizugawa, Kyoto 619-0215, Japan

Laser ion acceleration has caught significant attentions due to its various applications such as medical applications, ion beam fast ignition, and proton radiography. For medical applications, laser ion acceleration is expected to realize a compact and reliable ions source for the cancer therapy. One of the critical issues on laser-driven ion source is the enhancement of laser-accelerated ion energy, where protons with maximum energy of 200 MeV are requested from the medical point of view. The mechanism known as a target normal sheath acceleration (TNSA) has been widely investigated theoretically and experimentally, and it is shown that a relatively high power laser such as PW-class laser is needed for generating 200 MeV protons. Recently, high energy ions are observed from gas-cluster targets with relatively small laser energy [1], where 20 MeV/u ions are generated by using 4 TW laser pulse. We consider that these high energy ions, the energy of which is roughly one order higher than the TNSA energy scaling, are generated via formation and evolutions of magnetic dipole vortex [2]. In this paper, we investigate a detail of the ion acceleration via magnetic dipole vortex and derive an ion energy scaling. By the propagation of an intense laser pulse thorough underdense plasma, a dipole vortex is induced when the laser energy is almost depleted. In Fig. 1(a), an 50 55 60 ion distribution is plotted when a magnetic dipole vortex is formed. •V [(Ml] Electrons and resultant ions are pushed outward from the vortex, 10 (b) m forming an ion shell around the vortex and wall along the vortex axis. 1011 30 g Electron, ion and electric field distributions along the axis are plotted electron - e-field 20 in Fig. 1(b). The ion distribution has a sharp spike arid electrons are K located in front of it, which results in generation of strong electro-static 10 E field. This structure moves to the right together with expanding dipole J o 3 vortex. This leads to an ion acceleration by moving electric field. We

WeSl-5. Hollow microspheres - A novel target for staged laser-driven proton acceleration M. Burza1, A. Gonoskov23, G. Genoud1, A. Persson1, K. Svensson1, M. Quinn4, P. McKenna4, M. Marklund2, C.-G. Wahlstrom1 'Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden 2Department of Physics, Umea University, SE-901 87 Umea, Sweden 3Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod 603950, Russia 4SUPA, Department of Physics, University of Strathclyde, Glasgow, G4 0NG, United Kingdom

Laser-driven proton acceleration generates particle beams with interesting properties such as multi MeV energies and a very low longitudinal and transverse emittance. Its potential future applications range from proton imaging to proton cancer treatment and fast ignition in inertial confinement fusion.

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 43 c Abstracts - oral presentations 3

When a high intensity laser pulse strikes a thin foil target, a population of hot electrons is produced. Some of the electrons traverse the target and form an electrostatic sheath at the target rear side, which field ionizes surface contaminants such as hydrocarbons. Free protons are produced and accelerated along the target normal. This mechanism is known as Target Normal Sheath Acceleration (TNSA). However, the maximum proton kinetic energy obtained through TNSA is still insufficient for some applications, such as proton therapy. This is due to a poor energy coupling between the hot electrons and protons, partly as only a fraction of the hot electron population contributes to the quasi-static field at the rear side, and partly because this field enables acceleration during only a very short time.

In a recent TNSA experiment McKenna et al. observed protons emitted from the edges of a flat foil target [1]. The electrons responsible for that were part of the primary population of hot electrons, not contributing to the quasi-static field at the rear target surface. Instead they spread laterally with a speed close to the speed of light and set up a delayed sheath at the target edges, promoting proton emission there.

We explore the possibility to use these laterally spreading hot electrons to set up a spatially separate and temporally delayed field for post acceleration of protons following TNSA. For this we irradiate hollow microspheres of-50 pm diameter and sub-micron wall thickness. Laterally spreading hot electrons are guided along the spherical surface to the opposite side of the sphere, where protons accelerated to MeV energies through TNSA inside the sphere are passing through a micro machined exit hole and become post accelerated.

We will present our first experiments with hollow microspheres, conducted at the Lund High Power Laser Facility. The results show spatial and spectral features in the proton beam parameters that are different to those encountered in standard TNSA experiments with flat foil targets. The experimental results are compared with the outcome of PIC simulations.

References [1] McKenna et al.„ Phys. Rev. Lett. 98,145001 (2007)

WeSl-6. Dose-dependent biological damage of tumour cells by laser-accelerated proton beams S. D. Kraft1, C. Richter K. Zeil1, M. Baumann E. Beyreuther1, T. E. Cowan1, W. Enghardt1A3, L. Karsch2, L. Laschinsky2, E. LessmannVjj. Metzkes1, D. Naumburger2, R. Sauerbrey1, M. Schiirer2, U. Schramm 1 and J. Pawelke1,2 ' Forschungszentrum Dresden-Rossendorf (FZD), Bautzner Landstrafie 400, Dresden, Germany 2 OncoRay—Center for Radiation Research in Oncology, TU Dresden, Fetscherstr. 74, Dresden, Germany 3 Klinik fur Strahlentherapie und Radioonkologie, TU Dresden, Fetscherstr. 74, Dresden, Germany

Cancer therapy using protons or heavier ions such as carbon plays a more and more important role in oncology. In contrast to the widely used X-rays, the ions deposit their energy mainly in a small spatial region before they come so a stop (Bragg peak) and thus it is possible to deposit energy within the tumour in a more controlled way sparring the surrounding tissue. So far, the required accelerators are quit complex and costly, since laser accelerated ion technology has made large progress over the last years, it has been proposed to use lasers in order to replace conventional accelerators. To reach this goal, among obvious tasks as an increase in ion energy, precise dosimetry measurements for ultrashort ion bunches have to be established and the biological effectiveness of laser accelerated protons has to be determined.

44 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

We report on the first experiments, showing dose dependent biological damage of tumour cells by laser- accelerated protons [1], In order to apply the dose in a controlled way an energy filter system as well as a dedicated dosimetry system and an in-air cell irradiation site has been set up. The cells could be irradiated with protons of an energy range between 5 and 15 MeV applying doses of a few Gray within a few minutes. References [1] S. D. Kraft, C. Richter, K. Zeil et al. New J. Phys. in press (2010).

WeS2-l. Compact laser-produced plasma EUV sources for processing polymers and nanoimaging H. Fiedorowicz. A. Bartnik, R. Jarocki, J. Kostecki, M. Szczurek, P. Wachulak Institute of Optoelectronics, Military University of Technology, Warsaw, 00-908, Poland

Extreme ultraviolet (EUV) can be produced from a high-temperature plasma generated by interaction of high power laser pulses with matter. Laser plasma EUV sources are considered to be used in various applications in physics, material science, biomedicine, and technology. In the paper new compact laser plasma EUV sources developed for processing polymers and imaging are presented. The sources are based on a gas puff target formed by pulsed injection of a small amount of gas under high-pressure into a laser focus region. The use of the gas puff target instead of a solid target allows for efficient generation of EUV radiation without debris production [1], The compact laser plasma EUV source based on a gas puff target was developed for metrology applications [2, 3].

The EUV source developed for processing polymers is equipped with a grazing incidence axisymmetrical ellipsoidal mirror to focus EUV radiation in the relatively broad spectral range with the strong maximum near 10 nm. The size of the focal spot is about 1.3 mm in diameter with the maximum fluence up to 70 mj/cm2. EUV radiation in the wavelength range of about 5 to 50 nm is produced by irradiation of xenon or krypton gas puff target with a Nd:YAG laser operating at 10 Hz and delivering 4 ns pulses of energy up to 0.8 J per pulse. The experiments on EUV irradiation of various polymers have been performed. Modification of polymer surfaces was achieved, primarily due to direct photo-etching with EUV photons and formation of micro- and nanostructures onto the surface [4]. The mechanism of the interaction is similar to the UV laser ablation where energetic photons cause chemical bonds of the polymer chain to be broken. However, because of very low penetration depth of EUV radiation, the interaction region is limited to a very thin surface layer (<100nm). This makes it possible to avoid degradation of bulk material caused by deeply penetrating UV radiation. The results of the studies should be applicable in biomedical engineering.

The compact laser plasma EUV source has been also used in a microscope based on a Fresnel optics for nanoimaging. Quasi-monochromatic EUV radiation at 13.8 nm was obtained by selection of a single line from the argon plasma spectrum produced using the argon gas puff target. The Mo/Si ellipsoidal mirror of 80 mm in diameter and the 45° incidence angle was applied as the selector. Using the Fresnel lens with the outer zone width of 50 nm the spatial resolution (half-pitch) of 70 nm was obtained [5].

Acknowledgements. The research was supported by the Ministry of Science and Higher Education under the EUREKA project E! 3892 ModPolEUV, the Foundation for Polish Science under the HOMING 2009 Program (grant number HOM2009/14B) and the EC's 7. Framework Program (LASERLAB-EUROPE, ELI-PP and COST Action MP0601). References [1] H. Fiedorowicz, A. Bartnik, H. Daido, I.W. Choi, M. Suzuki, Optics Communications 184,161 (2000) [2] H. Fiedorowicz, A. Bartnik, R. Jarocki, J. Kostecki, J. Krzywinski, R. Rakowski, M. Szczurek, A. Szczurek, Journal of Alloys and Compounds 401, 99 (2005)

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 45 c Abstracts - oral presentations )

[3] R. Rakowski, A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, J. Krzywinski, J. Mikolajczyk, L. Pina, L. Rye, M. Szczurek, H. Ticha, P. Wachulak, Optica Applicata 36, 593 (2006) [4] A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, A. Szczurek, M. Szczurek, Applied Physics B 96, 727 (2009) [5] P. Wachulak, A. Bartnik, H. Fiedorowicz, Optics Letters (2010) - accepted for publication

WeS2-2. Attosecond shot noise Sandor Varro Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences H-1525 Budapest, POBox49, Hungary, E-mail: [email protected]

The spatio-temporal characteristics of electromagnetic radiation can be monitored on the basis of first order interference or higher-order correlation techniques, by measuring the moments of the field strength at different space-time points. In most cases the informaton is mediated by photoelectrons whose current - owing to the granular nature of electricity - is subject to particle noise. An attosecond pulse train (or an isolated pulse) is usually viewed as an extreme signal stemming from a nonlinear dipole moment associated to bound- continuum-bound electron transitions, containing very high-order harmonics of the exciting radiation [1]. As long as this source is approximated by an expectation value of the otherwise quantal dipole moment, the resulting attosecond radiation is automatically set to be a many-mode coherent radiation in the strict sense of quantum electrodynamics. Then, according to Glauber's quantum coherence theory [2], all the moments characterizing the correlations in such signals would factorize, giving no possibility to overcome the usual shot-noise limit. The question naturally arises, whether to what extent can attosecond pulses be considered as simply broad-band classical signals [3]? If they are not classical, then by what means could one sample them to study their spatio-temporal structure? Instead of first-order interference, we propose to carry out intensity- intensity correlation measurements on split nano-pixels [4], which are not sensitive against phase distortions. By changing the tilt angle of the impinging attosecond pulses with respect to the detector array, the modal structure of the pulses could be monitored by measuring the current-current correlations, and this would yield a delayed coincidence curve. We have modelled the attosecond pulses by many-mode quantum-mechanical phase eigenstates [5], and a contrast ratio 4/3 relative to the Poissonian shot noise level of the coincidence curve has been derived. Acknowledgements. This work has been supported by the Hungarian National Scientific Research Foundation OTKA, Grant No. K73728. References [1] Krausz F and Ivanov M, Rev. Mod. Phys. 81,163 (2009) [2] Loudon R 2000 7he Quantum Theory of Light (University Press, Oxford, 2000) [3] Papoulis A, Signal Analysis. (McGraw-Hill Book Company, New York, 1977) [4] Fabre C, Fouet J B and Maitre A, Optics Letters 25, No. 1/January 1, 2000 [5] Varro S, Fortschritte derPhys. 56, 91 (2008), arXiv:1004.2975vl [quant-ph] (2010)

46 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

WeS2-3. Time-dependant Bloch-Maxwell modelling of lmj, 200 fs seeded soft x-ray laser Ph. Zeitoun, E. Oliva, M. Fajardo, P. Velarde, D. Ros, S. Sebban Laboratoire d'Optique Appliquee, France Universidad Politecnica de Madrid, Spain Instituto Superior Tecnico, Portugal Laboratoire de Physique des Gaz et des Plasmas, France

Seeding of high harmonic generation in a soft x-ray plasma amplifier has been first proposed and tested by T. Ditmire and collaborators. The experiment demonstrated low amplification (*2), with a very strong background coming from the soft x-ray laser ASE. Later seeding experiments reached very high amplification factors (up to 600) in both gas [Ph. Zeitoun et al] and solid amplifiers [Wang et al]. Surprisingly, solid amplifiers extracted less energy (90 nj) than gas amplifier (~1 pj) with equivalent pump energy. We recently demonstrated that 50-100 pj is achievable with adequate plasma tailoring. However, this energy is still low as compared to the 10 mj per pulse demonstrated on the ASE soft x-ray laser running at PALS facility (Czech Republic). In order to model the seeding process of PALS soft x-ray laser, we developed a time-dependant Bloch-Maxwell model that solves coherently the pumping, amplification and saturation processes. We demonstrated that direct seeding, with femtosecond pulse, a soft x-ray plasma amplifier having gain duration of several 100s of picosecond cannot extract the stored energy keeping the output beam energy in the 100 pj range. We proposed and fully modelled a new seeding scheme that allows to achieve 10 mj, 200 fs soft x-ray laser.

WeS2-4. Study of electrons distribution produced by laser-plasma interaction on x-ray generation L. Nikzad1. R. Sadighi-Bonabi2 ' School of Optics and Laser, Tehran, Iran; 2 Department of Physics, Sharif University of Technology, Tehran, Iran;

In the present work, X-ray beams are generated from interaction of relativistic electron beams produced by interaction of 500 mj, 30 femtosecond Ti:sapphire laser pulses with thin solid targets such as lead, molybdenum and tungsten. After interaction of an intense pulsed laser with He gas-jet, a micron-scale laser produced plasma, creates and accelerates electron bunches, which propagate in the ion channel produced in the wake of the laser pulse. When an electron bunch is injected into the bubble in phase with its field, it will gain relativistic energies within very short distance. These accelerated electrons with Megaelectron-Volt energy and different distributions, can interact with targets to generate X-ray radiation with Kiloelectron-Volt energy, providing to be close enough to the gas-jet, where the relativistic accelerated electrons exist. Here, to determine the results, Monte Carlo simulation (MCNP-4C code) is employed to present Bremsstrahlung and characteristic X-ray production by quasi-Maxwellian and quasi-monoenergetic electron beams for three samples with different thicknesses. The outcome shows that for one specific electron spectrum and one definite target, the energy which the maximum characteristic x-ray flux takes place, varies with thickness. Also, for each material the energy which this maximum happens is constant for all thicknesses, for both produced electron spectra. For each sample, x-ray flux is calculated for different thicknesses and the thickness which the maximum characteristic x-ray flux occurs is obtained. Besides, it is concluded that by increasing the atomic number of the target, maximum X-ray flux moves towards higher energy. Also, comparison of the results for three targets and two electron distributions shows that by using quasi-monoenergetic electron spectra, more intense and narrower characteristic X-ray can be produced compared to the quasi-Maxwellian electron distribution, almost for all samples and thicknesses. The next-generation compact laser-based sources of energetic high- quality electrons and x-ray radiation can provide more effective technique for various applications in physics, Chemistry, Biology, and medicine.

47 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Key words: quasi-Maxwellian and quasi-monoenergetic electrons, intense laser-plasma interaction, Bremsstrahlung and characteristic X-ray, Monte Carlo simulation (MCNP4 code)

WeS2-5. Samarium space resolved measurements E. Louzon1, Z. Henis1,1. Levi1, G. Hurvitz1, Y. Ehrlich1, M. Frankel1, S. Maman1, E. Raicher1, A. Malka1, P. Mandelbaum2, A.Zigler3 •Soreq Research Center, Yavne 81800, Israel; Jerusalem College of Engineering, Ramat Beth Hakerem, 91035 Jerusalem, Israel; 3Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel

Spatially resolved x-ray spectra of samarium laser produced plasma are presented. Space resolved spectra have highly importance in the study of ionization dynamics and hydrodynamics of laser generated plasmas. X-ray spectroscopy is a powerful mean to estimate the plasma properties as electron temperature and density. It is also a mean to test the accuracy of kinetic models describing plasmas under conditions that are out of local thermodynamic equilibrium (LTE). Presented here is detailed spectroscopic identification of space resolved lines from which one could infer the evolution of the plasma parameters. A set of experiments is presented with varied laser intensities. The measurements show higher length of plasma expension when one increases the laser intensities. Also shows here changes in the dominant contribution of different ionization stages and in the relative line intensities for different incident laser intensities. Spectral lines emitted by Mn-like (Sm37+, ground 3d7) to Zn-like (Sm32+, ground 3d104s2) were identified. From the many identified spectral lines we present specific Ni-like lines (Sm34+, ground 3d10) that are useful for the diagnostic of the plasma parameters and testing of the theoretical models. Simple model was developed using HULLAC code to calculate Ni-like lines ratios. Comparing the theoretical results to the experimental space resolved measurements shows a definite behavior of self absorption close to target surface. Those results predicted high densities near the target, above 5 x 1021 cm'3. Presented here is an estimation of the electron density and temperature in space.

WeS2-6. Cross focusing of two coaxial Gaussian beams with relativistic and ponderomotive nonlinearity Prerana Sharma. R.P. Sharma 1. Department of Physics, Ujjain Engineering College, Ujjain, M.P - 465010, India 2. Centre for Energy Studies, Indian Institute of Technology, Delhi -110 016, India

This paper presents the cross focusing of two high power lasers by taking off-axial contribution of the laser beams in a collisionless plasma. On account of relativistic and ponderomotive nonlinearities two laser beams affect the dynamics of each other and cross-focusing takes place. The expressions for the laser beam intensities by using the eikonal method have been derived. The contribution of r2 and r4 terms is incorporated in the present analysis. By expanding the eikonal and, the other relevant quantities up to the fourth power of r, the solution of the pump laser beam has been obtained within the extended-paraxial ray approximation. Filamentary structures of the laser beams are observed due to relativistic and ponderomotive non-linearity. It is observed that the focusing of the laser beams become fast in the extended-paraxial region. Using the laser beam and the plasma parameters, appropriate for beat wave process, the filaments of the laser beams have been studied and relevance of these results to beat wave process has been pointed out.

48 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations 3

WeS3-l. Genuine two-fluid computations of laser-plasma interaction for generation of nonlinear force driven plasma blocks F.Nafari1 E.Yazdani2, B.Malekynia3, M.Ghoranneviss4 'Department of Physics, Malayer Branch, Islamic Azad University, Malayer, Iran 2 Department of Physics, Amirkabir university of technology, Tehranr, Iran 3 Department of Physics, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran 4Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran-Poonak, Iran

Anomalous interaction of picosecond laser pulses of terawatt to petawatt power is due to suppression of relativistic self-focusing if prepulses are cut-off by a contrast ratio higher thanlO8 .Resulting non-linear ponderomotive forces induced at the skin-layer interaction of a short laser pulse with a proper preplasma layer produced by the laser prepulse in front of a solid target accelerate two thin (a few pm) quasi-neutral plasma blocks, propagating in forward and backward directions, backward moving against the laser light (ablation) and forward moving into the target. This compressed block produces an ion current density of abovelOnA/cm2. This may support the requirement to produce a fast ignition deuterium tritium fusion at densities not much higher than the solid state by a single shot pw-ps laser pulse. With studying skin-layer subrelativistic interaction of a short (< 1 ps) laser pulse with an initial Rayleigh density profile in genuine two-fluid hydrodynamic model ,time and spatial distributions of ion block temperature are presented.

References [1] E. YazdaniI,Y. Cang, R. Sadighi-bonabi, H. Hora and F. Osman ,Laser and Particle Beams (2009), 27, 149-156. [2] Y. Cang,F. Osman, H. Hora, J. Zhang,J. Badziak, J. Wolowski, K. Jungwirth.K. Rohlena and J. Ullschmied, J. Plasma Physics (2005), vol. 71, part 1, pp. 35-51

WeS3-2. Issues connected with SBS PCM based self-navigation of laser drivers on injected pellets

M.Kalal'. H.J.Kong2, and O. Slezak1 'Czech Technical University in Prague, PNSPE, Brehova 7, 115 19 Prague 1, Czech Republic 2 KAIST, Dept. of Physics, 373-1 Gusong-dong, Yusong-gu, Daejeon, 305-701 Republic of Korea

In practice, there are many serious obstacles complicating the classical direct drive IFE scheme - even putting in doubts its practical feasibility. Among the most serious ones is the insufficient predictability of the injected pellets' trajectories resulting from their expected interactions with remnants of previous fusion explosions due to the considered 5-10 Hz repetition rate. This is one of the reasons why the indirect drive scheme - despite its higher demand on laser energy - seems to be currently considered a more serious IFE candidate. The corresponding hohlraum targets are by three orders of magnitude heavier compared to their direct drive counterparts, thus allowing for more reliable prediction of their trajectories. In this contribution, a recent progress achieved in the stimulated Brillouin scattering (SBS) phase conjugating mirror (PCM) based inertial fusion energy (IFE) approach proposed recently as an alternative to the IFE classical approach mentioned above, will be reported. By taking care of automatic self-navigation of every individual laser beam on injected pellets with no need for any final optics adjustment, this technology is of a particular importance to the direct drive scheme [ 1 ]. Conceptual design of one typical laser driver will be shown and its features discussed. Three distinct stages of this process can be identified: (i) at the right moment (determined by careful tracking), when the injected pellet is approaching its best interaction position, low energy seeding laser pulse (glint) is sent to illuminate the pellet;

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 49 c Abstracts - oral presentations ) (ii) reflected seeding laser pulse is collected by the focusing optics and amplified on its way to the SBS PCM cell; (iii) amplified pulse is reflected by the SBS PCM cell, amplified once again on its return, converted to higher harmonic (being now above threshold of this non-liner process), and automatically aimed at the moving pellet by the target displacement compensation system for its final high power pellet irradiation. This is a completely passive system having its optical components appropriately designed for every individual channel taking advantage of their index of refraction dependence on the wavelength. In comparison with the earlier design, an upgraded scheme was developed with the low energy illumination laser beam entering the reactor chamber through the same entrance window as used by the corresponding high energy irradiation laser beam. The pellet survival conditions in the period between its low energy illumination and subsequent high energy irradiation were studied and the upper limits on the allowed energies absorbed for both DD and DT fuels were found [2], Results of experimental verification of this improved design will be reported. In these experiments for the fist time a complete setup including the pellet (realized by the static steel ball) was employed. Issues of the pellets with cones and parasitic effects of perpendicular SBS will be also discussed. Acknowledgements

This research was supported by International Atomic Energy Agency Research Contracts No. 13781 & 13758.

References [1] M. Kalal, H.J. Kong, M. Martinkova, O. Slezak, and J.W. Yoon, J. Korean Physical Society 56, 184 (2010). [2] M.Kalal, O.Slezak, H.J. Kong, J.S. Shin, E.R. Koresheva, and S.A. Startsev, J. Fusion Energy (in print)

WeS3-3. Analysis of the laser materials nanostructurization mechanisms I. N. Zavestovskava P.N.Lebedev Physical Institute,53, Leninsky pr„ 119991 Moscow,Russia

Modification of the structure and phase properties of the metal and alloy surface layers under superfast cooling velocities are widely used to produce superfine crystalline and amorphous structures with an application of the laser pulses of different duration. Rapid development of ultrashort lasers opens up possibilities for new applications of material precision treatment as compared to conventional lasers. Nanostructuring of the metal surface layers makes use of femtosecond laser pulses with the intensities close to the threshold ones, where one observes the metal melting in a small volume without any significant ablation. After the end of the laser pulse the melt is rapidly crystallized due to the heat propagation into the specimen depth. Due to superfast colling (109 K/s and higher) the size of the produced crystallites may be compared with an interatomic spacing. In this case an amorphous layer may be formed, if the cooling velocity exceeds the freezing rate. The formation of a superfine crystalline or amorphous surface structures under the action of the laser pulses are called in literature "laser glazing". In case of a femtosecond laser pulse the material heating and melting processes take place under essentially nonlinear and non-equilibrium conditions. However, the kinetics of the melt cooling after the action of a supershort laser pulse is defined, finally, by the velocity of heat propagation into the material depth, and for the metals this velocity makes about 1013 - 1015 K/s. So, the time of cooling makes the value more than 1012s. This means that one can make use of a heat model applied in classical consideration of the crystallization kinetics. The crystallization kinetics of metals from the melt under superfast cooling velocities realized in the treatment of the materials by ultrashort laser pulses has been studied. An explicit solution to kinetic equation for the size distribution function of crystalline phase nuclei at the fast cooling of the melt was analyzed analytically and numerically. The use has been made of physical preconditions for the crystallization process practically realized at superfast cooling; the existence of a sufficiently large number of crystal nuclei of supercritical size and a plate-type shape of the nuclei. An average size of crystallites has been defined, as well as the volume fraction of crystallized phase. The amorphyzation criterion for the melt cooling velocity is determined.

50 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 50 c Abstracts - oral presentations )

The presented expressions for the crystal nuclei size and the new phase volume have been used to describe the experiments on micro- and nanostructuring of the metal surface layers under the action of femtosecond laser pulses. Acknowledgments This work was supported by Rassian Academy of Science(grants 70F, 2IP), Russian Foundation for Basic Research (grant 09-02-00615), RF Ministry of Education and Science (grant 2009-1.1-122-052-025)

WeS3-4. Interaction of low coherent laser radiation with matter Alexander N. Starodub P. N. Lebedev Physical Institute of the RAS, Moscow, Russia

A project for a hybrid nuclear reactor with a laser thermonuclear source of neutrons [1,2] has initiated a search for new physical approaches to creation of a laser driver [3] and for new methods of diode pumping of the driver active elements [4,5].

The performed studies have demonstrated that a laser based on the generation and amplification of radiation with controllable coherence has a number of advantages as compared to conventional schemes of lasers. The carried out experiments have shown a possibility of suppression of small-scale self-focusing, formation of laser radiation pulses with required characteristics, simplification of an optical scheme of the laser, good matching of laser-target system, and achievement of homogeneous irradiation and high output laser energy density without using the conventional correcting technique (phase plates, adaptive optics, space filters, etc.).

The results on studying the physical processes in targets having different design and composition, including the volumetric-structure targets irradiated by a laser with a low coherent radiation, are presented and discussed. In particular, such important laser-matter interaction phenomena are investigated as the absorption and scattering of the laser radiation, the laser radiation harmonic generation, X-ray generation, and the conversion of laser radiation into the second harmonic by means of nonlinear crystals.

A nonlinear transparency of the laser irradiated volumetric-structure targets has been observed. Such a transparency is realized in a wide range of parameters of the laser radiation and the volumetric-structure targets, and is defined by the conditions for plasma formation and laser radiation absorption in the plasma, as well as the plasma dynamics.

Acknowledgements This work is partially supported by the Russian Foundation for Basic Researches (grants ## 07-02-01148, 07- 02-01407, 10-02-00113), Program of the RAS "Nonlinear optical methods and materials for new generation of laser systems" and the Federal Target Program "Research and scientific-pedagogical cadres of innovative Russia" (grant* 2009-1.1-122-052-025).

References [1] N.G. Basov, L.P.Feoktistov and V.N. Subbotin, Vestnik of RAS 63, 878 (1993). [2] L.P. Feoktistov, Zh. Matematicheskoe Modelirovanie 7, No. 3, 41 (1995). [3] S.I. Fedotov, L.P. Feoktistov, M.V. Osipov and A.N. Starodub, J. Russian Laser Research 25, 79 (2004). [4] A.P. Bogatov, A.E. Drakin, G.T. Mikaelyan, D.R. Miftahutdinov, V.I. Stadnichuk and A.N. Starodub, Kvantovaya Electronika 36, 302 (2006). [5] A.P. Bogatov, A.E. Drakin, G.T. Mikaelyan, D.R. Miftahutdinov and A.N. Starodub, Kvantovaya Electronika 38, 805 (2008).

51 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

WeS3-5. Laser wakefield dynamics and high gradient acceleration of short electron bunches in guiding structures N. E. Andreev1. S. V. Kuznetsov1, M. E. Veysman1, B. Cros2, P. Mora3, C-G. Wahlstrom4 'Joint Institute for High Temperatures ofRAS, Russian Academy of Sciences, Moscow, Russia 2Laboratoire Physique Gaz et Plasmas CNRS - Universite Paris-Sud 11, Orsay, France 3Centre de Physique Theorique, CNRS, Ecole Polytechnique, Palaiseau Cedex, France "•Department of Physics, Lund University, Lund, Sweden

Nonlinear dynamics of high gradient accelerating plasma wakefields generated by a short intense laser pulse in guiding structures is analyzed on the base of elaborated spectroscopic diagnostics [1] and full scale modeling [2]. The results of last experiments [3] on the plasma wave excitation over a length of up to 8 centimetres are demonstrated using laser guiding of intense laser pulses through hydrogen filled glass capillary. Analytical predictions of the laser frequency red shift due to the wakefield excited in the capillary waveguide are confirmed by self-consistent modelling results. The role of ionization blue shift and nonlinear laser pulse and wakefield dynamics on the spectrum modification is analyzed. The plasma waves are diagnosed by spectral analysis of the transmitted laser radiation. The dependence of the spectral red shift, as well as the laser spectra, measured as a functions of filling pressure, capillary tube length and incident laser energy, are in excellent agreement with simulation results [2]. The longitudinal accelerating field inferred from the full scale modelling is in the range 1-10 GV/m. High gradient acceleration of electrons by plasma wake waves generated in plasma by short intense laser pulses is analyzed. The influence of the loading effect and initial emittance on the quality of accelerated electron bunches is studied. Analytical predictions confirmed by the fully self-consistent 3-D modeling by code LA- PLAC of the proposed scheme of electron bunch injection in front of the laser pulse open an opportunity for the production of low emittance and energy spread electron bunches of GeV energies and submicron sizes [4]. The important feature of the discussed scheme of bunch compression and acceleration in a moderately nonlinear wakefield is a controllable phase of the accelerated electron bunch, determined by the laser pulse timing, which permits subsequent use of these bunches for further multistage acceleration in future colliders to higher energies beyond GeV range. Acknowledments This work was supported in part by the Programs on fundamental research of Russian Academy of Sciences, by the Russian Foundation for Basic Research - CNRS PICS program (grant 07-02-92160), by the European Community -New and Emerging Science and Technology Activity under the FP6 "Structuring the European Research Area" programme (project Euro LEAP, contract 028514). This work was also supported by the Swedish Research Council and the Knut and Alice Wallenberg Foundation. References ['] N.E. Andreev and M.V. Chegotov, JETP 101, 56-63 (2005). [2] N.E. Andreev, K. Cassou, F. Wojda, G. Genoud, M. Burza, O. Lundh, A. Persson, B. Cros, VE. Fortov and C-GWahlstrom, New Journal of Physics 12, 045024 (2010). [3] F. Wojda, et al, Phys. Rev. E 80, 066403 (2009). [4] N.E. Andreev, S.V. Kuznetsov, B. Cros, V.E. Fortov, G. Maynard and P. Mora, Plasma Phys. Control. Fusion, in press. (2010).

52 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

WeS3-6. Outbursts of fast ions and generation of DD-neutrons by sub-nanosecond laser irradiation at intensities up to 5x10"' W cm"2 1. Krasa1. A. Velyhan1, D. Margarone1, E. Krousky1, K. Jungwirth1, L. Laska1, K. Rohlena1, J. Skala1, M. Pfeifer1, J. Ullschmied| L. Rye3, P. Parys3, J. Wolowski3, D. Klir4, J. Kravarik4, K. Rezac4, P. Kubes4 rInstitute of Physics, ASCR, v.v.i., 182 21 Prague 8, Czech Republic 2 Institute of Plasma Physics, ASCR, v.v.i., 182 00 Prague 8, Czech Republic 3 Institute of Plasma Physics and Laser Microfusion, 00-908 Warsaw, Poland 4 Czech Technical University, 166 27 Prague 6, Czech Republic

We exposed massive slab graphite and deuterized polyethylene targets to laser intensities up to 5X1016 WI cm2 varying both the laser energy and the position of the laser beam focus with respect to the target surface. The sub-nanosecond Prague Asterix Laser System (PALS) operating at a fundamental wavelength of 1315 nm was employed as a driver. Carbon ion currents reaching values up to 15 kA/sr and maximum ion energies of ~1 MeV/amu in the downstream direction (i.e. in the backward direction with respect to the incident laser beam) are reported. The maximum energy of protons was estimated to be ~2 MeV. The irregular shape of time- of-flight (TOF) spectra is caused by plasma outbursts, whose growth results in ion current pulsations with a period of about 5 ps during the laser-plasma interaction. TOF spectra of neutrons emitted from deuterized polyethylene plasma were measured in the upstream (forward) direction with the use of scintillation detector. The time-resolved signal of the scintillation detector induced by hard X-rays was analyzed. The neutron yield measured with the use of bubble neutron detectors reached values of up to lxlO7 neutrons per shot.

Th-1. Giant X-Ray Nonlinearities in the Kiloelectronvolt Regime E. Racz1,2, S.F. Khan1, A.B. Borisov1, S. Poopalasingam1, J.C. McCorkindale1, S.J. Ward7, J.W. Longworth1-6, A.E. Felder13, J. Boguta1, J. Zhao1, C.K. Rhodes13'4-5 1 Laboratory for X-ray Microimaging and Bioinformatics, Department of Physics, University of Illinois at Chicago, Chicago, II60607-7059, USA 2 KFKI Research Institute for Particle and Nuclear Physics, EURATOM Association, PO Box 49,1525 Budapest, Hungary 3 Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607-7062, USA 4 Department of Computer Science, University of Illinois at Chicago, Chicago, IL 60607-7042, USA department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois, 60607-7053, USA department of Physics, Illinois Institute of Technology, Chicago, Illinois, 60616, USA 'Department of Physics, Hamilton College, Clinton, New York, 13323, USA

Copious Xe(M) (~1 keV) and Xe(L) (~4.5 keV) production induced by intense femtosecond 248 nm pulse excitation of Xe clusters is a well established phenomenon [1-3]. Present studies of the characteristics of Xe(L) amplification in plasma channels [3] have dramatically revealed the presence of very strong nonlinear dispersive and absorptive processes in the x-ray range that are illustrated in Figure 1. The dispersive nonlinearity is illustrated in panels (a) and (b) by the clear action of self-focusing. The corresponding absorptive nonlinearity is shown in panel (c); intense Xe(M) radiation at ~1 keV produces Xe L-shell vacancies that generate corresponding Xe(L) emission, an observation requiring the absorption of a minimum of 5 ~1 keV photons. Since the linear Kramers-Kronig relation has a nonlinear extension, these two phenomena are in natural alliance. Fig.l. Simultaneous single-pulse pinhole camera Xe(M) (~1 keV) and Xe(L) (-4.5 keV) images of x-ray production and propagation in a 248 nm driven channel in a Xe cluster medium produced with a 1.4 mm diameter circular nozzle, (a) Characteristic Xe(M) propagation illustrating both copious x-ray production and

31st ECLIM . 6-10 September, 2010 - Budapest, Hungary 53 c Abstracts - oral presentations ) the self-focusing of the originally annular Xe(M) beam, (b) 3-D view of panel (a) illustrating the collapse of the annular configuration of the Xe(M) beam into a focused axial structure. The self-focusing action is developed in the Xe cluster medium in a region that is not directly excited by the 248 nm pulse, (c) Simultaneously recorded Xe(L) emission that spatially overlaps the image in panel (a). The use of a 7.5 ^m thick Ti filter suppresses the Xe(M) signal by a factor of ~10 ; hence, only the Xe(L) component is detected. This image demonstrates that sufficiently intense Xe(M) radiation can produce strong Xe(L) emission by a nonlinear coupling. Of particular significance is the Xe(L) production observed at the end of the channel with a maximum spatial breadth of -200 |im.

Acknowledgement This research was funded by DARPA on contract no. DAAD10-01-C-068 through the Army Research Laboratory. The views, opinions, and/or findings contained in this article/presentation are those of the author/presenter and should not be interpreted as representing the official views or policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the Department of Defense. A: Approved for public release, distribution unlimited. References [1] A. Mc Pherson, B.D. Thompson, A.B. Borisov, K. Boyer, and C.K. Rhodes, Nature 370, 631 (1994). [2] A.B. Borisov, J.W. Longworth, A. McPherson, K. Boyer, and C.K. Rhodes, J. Phys. B 29, 247 (1996). [3] A.B. Borisov, E. Racz, P. Zhang, J.C. McCorkindale, S.F. Khan, S. Poopalasingam, J. Zhao, C.K. Rhodes, J. Phys. B 41, 105602 (2008).

Th-2. Laser acceleration and high field science T. Tajima* . Faculty of Physics, Ludwig Maximilian University, Garching, Germany *Blaise Pascal Chair, Ecole Normale Superieure

With the intense laser entering the relativistic regime for some time, the vision of laser wakefield acceleration has become a reality. With the energy of relativistic laser further increasing, we now envision a regime of greater accelerated energies as well as new regimes of acceleration, including ions. With the 100J class laser now soon in hand, we foresee multi-staged acceleration reaching beyond lOOGeV, a serious energy threshold. With this class ion acceleration also enters into a new regime where ions too become relativistic and thus monoenergy. We will discuss TeV and PeV laser acceleration in this talk. In addition to laser-based collider possibility (for which we advocate laser development with high efficiency and high repetition rate), we also envision possibility of conducting fundamental physics research based on non-collider approaches. PeV energies will allow us to feel the texture of vacuum. Meanwhile, high intensity fields of laser could excite and resonate with 'vacuum modes', for which we will elaborate. Finally, I will mention some of societal applications that may be derived from these laser technology development spurred by the interest into fundamental physics.

54 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations

Th-3. High gradient acceleration with the FLAME laser at LNF-Frascati Leonida A. Gizzi * ILIL, Istituto Nazionale di Ottica-INO, UOS "Adriano Gozzini", CNR, Pisa, Italy and Istituto Nazionale di Fisica Nucleare (INFN), Sez. Di Pisa, Italy * on behalf of the FLAME commissioning team

Following a successful decade of exploration of the basic principles of laser-plasma acceleration (LPA), dedicated PW-scale systems are being built around the world to demonstrate operation of laser-plasma accelerators at higher energy and beam quality. The next decade will be crucial for the establishment of LPA as a mature approach to the next generation of accelerators, with potential impact on future international collaborative programmes in high-energy physics. The Italian National Istitute of Nuclear Physics, in collaboration with the Italian National Research Council has promoted and funded a LPA programme which included a range of activities, including LPA with self-injection and external injection and the generation of tuneable X-ray radiation from Thomson scattering of LPA electron bunches for medical applications. The commissioning of the 300 TW Frascati LAser for Multidisciplinary Experiments is now being completed and the a test experiment on electron acceleration with self-injection is in progress. An overview of the LPA programme will be given with a detailed description of the FLAME installation and the planned test experiment.

Th-4. Radiation sources based on laser plasma accelerators Cs. Toth*, M. Bakeman, A. J. Gonsalves, C. Lin, N. Matlis, K. Nakamura, J. Osterhoff, G. Plateau, S. Shiraishi, T. Sokollikj J. van Tilborg, C. G. R. Geddes, C. B. Schroeder, E. Esarey, and W. P. Leemans LOASIS Program, Lawrence Berkeley National Laboratory (LBNL) - Berkeley, CA, USA *[email protected]

Experimental results of the LOASIS (Lasers, Optical Accelerator Systems Integrated Studies) Laboratory of LBNL achieved with the routine operation of a 10 TW (Godzilla) and a 100 TW class laser system (TREX) are reviewed. Recent laser plasma acceleration (LPA) results include GeV electron beam production in 3-cm capillary discharge [1], controlled injection via longitudinal density tailoring in a plasma channel [2], LPA electron beam control using quadruple magnets, and e-beam characterization using optical transition radiation (OTR), phosphor screen monitors, and cavity based beam pointing monitors (BPMs). Progress on the development of an undulator-based e-beam diagnostic will also be discussed. These recent LPA experimental results open up new opportunities to develop compact, extremely bright light sources with wavelengths spanning the extreme edges of the electromagnetic spectrum from the THz waves, through the deep UV and hard X-rays, to multi-MeV gamma radiation. The physical processes in these light generation methods are • Coherent transition radiation generated by the LPA e-beam at a plasma-vacuum interface for THz radiation generation [3], • Undulator radiation in a LPA-driven free electron laser (FEL) for XUV generation [4]. • Betatron motion and emission of synchrotron radiation from the accelerated electrons in a plasma channnel for keV-range X-ray generation. • Thomson scattering of visible laser light on LPA electrons for gamma ray production. Design of experiments and early results of measurements performed in the LOASIS Program at LBNL, as well as the prospects for light source applications based on LPAs will be reviewed.

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 55 c Abstracts - oral presentations )

Acknowledgment. This work has been supported by the Director, Office of Science, Office of High Energy Physics, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and DTRA. References [1] W.P. Leemans, B. Nagler, A.J. Gonsalves, Cs. Toth, K. Nakamura, C.G.R. Geddes, E. Esarey, C.B. Schroeder, and S.M. Hooker, Nature Physics, 2, 696-699 (2006). [2] C.G.R. Geddes, K. Nakamura, G.R. Plateau, Cs. Toth, E. Cormier-Michel, E. Esarey, C.B. Schroeder, J.R. Cary, and W.P. Leemans, Phys. Rev. Lett. 100, 215004 (2008). [3] W.P. Leemans, C.G.R. Geddes, J. Faure, Cs. Toth, J. van Tilborg, C.B. Schroeder, E. Esarey, G. Fubiani, D. Auerbach, B. Marcelis, M.A. Carnahan, R.A. Kaindl, J. Byrd, and M.C. Martin, Phys. Rev. Lett. 91, 4802- 4805 (2003). [4] C.B. Schroeder, W.M. Fawley, F. Griiner, M. Bakeman, K. Nakamura, K.E. Robinson, Cs. Toth, E. Esarey, and W.P. Leemans, in Advanced Accelerator Concepts. Amer. Inst, of Phys. Conf. Proc. 1086, (AIP Press, Melville, NY, 2009) pp. 637-642.

Th-5. ICF fast ignition with ultra-relativistic electron beams Claude Deutsch-. Jean-Pierre Didelez2 1LPGP Universite Paris-Sud, (UMR-CNRS 8578) Bat. 210, P-91405 ORSAY, France 2IPN Universite Paris-Sud, Bat. 100, F-91405 ORSAY, France

In contradistinction to the main-stream fast ignition scenario based on collisional stopping in the compressed DT-fuel of relativistic electron beams (REB) in the 1-2 MeV energy range (ER) [1], we consider an ultra- relativistic extention of the Malkin-Fisch [2] attempt at using REB in the several tenths of MeV ER, and stopping them in target through strong induced Langmuir turbulence. We stress therefore the additional and substantial contribution to REB stopping of strongly inelastic reactions such as the Trident production of electron-positron pairs.In the 100 MeV and higher ER bremsstrahlung turns significant and hard Gamma come also into play to enhance these processes. We thus specifically stress electro-disintegrating deuterons and tritons, firstly in nucleons and eventually at higher energy with negative pion production included. In the latter case, it seems attractive to consider pion-catalyzed DT fusion in a very dense and hot plasma with no sticking. This claim is supported by preliminary estimates based on Debyelike diatomic plasma orbitals. More interplays between Resulting positrons and pions of either sign are also seen to contribute to in situ stopping of ultra-relativistic REB.The latter would then drive efficiently a fast ignition target with a significantly reduced beam intensity and without hole boring issues.

References [1] - C. Deutsch, H. Furukawa, K. Mima, M. Murakami and K. Nishihara, Phys. Rev. Letters, 77, 2483 (1996), and also K.V. Starikov and C. Deutsch, Phys. Plasmas 14 022704, (2007). [2]- V.N. Malkin and N.J. Fisch, Phys. Rev. Letter. 89,125004 (2002).

Th-6. Theoretical progresses on electron and ion acceleration and relativistic short-pulse generation at SIOM Baifei Shen State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P. O. Box 800-211, Shanghai 201800, China

The triggering of wave-breaking in a three-dimensional laser plasma wake (bubble) with a nanowire is investigated. The Coulomb potential from the wire is used to disturb the wake field to initialize the wave- breaking. Controlled electron acceleration in the bubble regime is controlled by optimizing the plasma density. The origin of beam disparity in emittance and betatron oscillation orbits, in and out of the polarization plane

56 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations ) of the drive laser of laser-plasma accelerators, is explained in terms of betatron oscillations driven by the laser field with simulation and a simple model [1]. Proton trapping and acceleration by an electron bubble-channel structure in high-intensity laser interaction with high density plasma is investigated by using three-dimensional particle-in-cell simulations. It is shown that protons can be trapped, bunched, and efficiently accelerated for appropriate laser intensity and plasma density, and the proton acceleration is enhanced if the plasma consists mainly of heavier ions such as tritium. Theory and simulation of ion acceleration with electrostatic shock is given in detail. Electrostatic shock driven by linearly and circularly polarized laser pulse are compared. Multi stage shock acceleration for ultra thin foils is used to increase the efficiency of laser acceleration [2]. The effect of plasma temperature of laser intensity is discussed. A sandwich target design with a thin compound ion layer between two light-ion layers and a micro-structured target design are proposed for obtaining efficiently monoenergetic heavy-ion beams [3], The foil thickness for light pressure acceleration is studied [4]. Quasi- single- cycle relativistic laser pulse is generated by laser-foil interaction[5] References [1] K. Nemeth, Baifei Shen et al., Laser-driven coherent betatron oscillation in a laser-wakefield cavity, Phys. Rev. Lett. 100, 095002 (2008). [2 Xiaomei Zhang, Baifei Shen et al., Multistaged acceleration of ions by circularly polarized laser pulse: Monoenergetic ion beam generation, Phys. Plasmas 14, 073101 (2007) [3] Liangliang Ji, Baifei Shen et al., Generating Monoenergetic Heavy-Ion Bunches with Laser-Induced Electrostatic Shocks, Phys. Rev. Lett. 101, 164802 (2008). [4] Liangliang Ji, Baifei Shen et al., Comment on "Generating High-Current Monoenergetic Proton Beams by a Circularly Polarized Laser Pulse in the Phase-Stable Acceleration Regime", Phys. Rev. Lett. 102, 239501(2009) [5] Liangliang Ji, Baifei Shen et al., Quasi-single-cycle relativistic laser pulse generation by laser-foil interaction, Phys. Rev. Lett. 103, 215005 (2009).

Th-7. Radiation pressure acceleration on Astra Gemini. P S Foster13', C Brenner2, M Borghesi3, F Cameron1, D C Carroll2, N Dover4, P Gallegos2, J Green1, P McKenna2, Z Najmudin^D Neely1, D Neville1, C Palmer, R Pattathil1, R Prasad3, K Quinn3, A Robinson1, L Romagnani3, C Spindloe1, M Streeter1, S Ter-Avetisyan3, O Tresca2 and M ZepP 1 Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxon, UK 2SUPA, Department of Physics, University of Strathclyde, Glasgow, UK 'Department of Physics and Astronomy, Queens University Belfast, Belfast, UK department of Physics, Imperial College, London, UK

Laser-accelerated proton beams have numerous potential applications ranging from fundamental physics to medicine. Controlling and enhancing their brightness, energy etc is an extremely active area of current research. The work presented here details the results of a recent experiment exploring laser interactions with ultra-thin foils within the intensity range 1018 to 1020 Wcm 2 where both linear and circular polarisations and normal and oblique angles of incidence were investigated. Interesting scaling relations for the effect of intensity on the maximum proton beam energy is presented. In addition, observations of the effect of high and low contrast on ion beam collimation are also shown. This work was carried out using the Astra Gemini Laser, at the Rutherford Appleton Laboratory, which is a Ti:Sapphire Petawatt laser system with a repetition rate of 1 shot/minute. To make use of the high-repetition rate, micro-channel plates and ultra-fast scintillator spectrometers were implemented and details of the calibration method and preliminary results are also presented here. This detection method offers immediate feedback enabling the online optimisation of interaction conditions.

57 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Th-8. Experiments on the indirect heating of low density aerogels for applications in heavy ion stopping in plasma O.N. Rosmei1. A. Blazevic1, N. Suslov2, A. Kunin2, A. Pinegin2,, D. Schafer3,Th. Nisius3,Y. Zhao4, T. Rienecker5, J. Wiechula5,jN. Orlov6, V. Bagnout1, U. Eisenbarth1, G. Vergunova7, N. Borisenko7, N. Zhikov2, V. -J Vatulin2, Th. Wilhein3, Th. Stohlker1, V. Fortov6 'Geselschaftfiir Schwerionenforschung, Darmstadt, Germany 2VNIIEF-Sarov, Russia 3Reihn-Arc-Campus Remagen, Germany 4Institure of Modern Physics, Lanzhou, China 5University of Frankfurt am Main, Germany 6Joint Institute for High Temperatures, Moscow, Russia 7Lebedev Physical Institute, Moscow, Russia

The unique combination of a Petawatt High-Energy Laser System for Ion beam experiments - "Phelix" (Nd:glass, 1053nm, 300-500 J, l-15ns) [1] and intense heavy ion beams of the UNILAC accelerator at GSI-Darmstadt allow creating and probing of hot plasmas with a density of some percentage of solid-state density. The experimental program aims at the investigation of fundamental features of heavy ion stopping in ionized matter in view of promising applications for the Heavy Ion Fusion and astrophysics [2, 3]. For combined experiments on the interaction of heavy ion beams with ionized matter (GSI) a high density plasma target with homogeneous in time (~ 5 ns) and space (~lmm) plasma parameters is required. For these purposes we are developing the combined target which consists on the Gold hohlraum (converter) and low Z foam target heated by the hohlram radiation before probed by an ion bunch. Foam targets are rather promising due to the effective conversion of the deposited radiation energy into the internal plasma energy and slow hydrodynamic response on the heating. Direct irradiation of the Gold converter walls with a nanosecond pulse delivered by the PHELIX-laser system (GSI) leads to hohlraum radiation spectra in the photon energy range of 50-500 eV. Expected temperatures of the foam targets heated by this radiation amount to 20-30 eV at electron densities of 1021 cm"3. The results of the last hohlraum experiments carried out at PHELIX-laser energies of 200 -250 J will be presented. In experiments the hohlraum radiation field, the conversion efficiency of the laser energy into soft X-rays, duration of the soft X-ray pulse, and parameters of the heated with X-rays foam targets have been measured. Aknowlegments This work is supported by ISTC#2264 grant. References: [1]. Bagnoud, V.; Aurand, B.; Blazevic, et al., Commissioning and early experiments of the PHELIX facility. Appl Phys B, DOI 10.1007/s00340-009-3855-7 (2009) [2], R. Bock, I. Hoffmann and R. Arnold, Nucl. Sci. Appl 2 (1984) 97 [3]. C. Deutsch, Ann. Phys. 11 (1986) 1 [4], A.M. Khalenko, N.G. Borisenko et al, Laser and Particle Beams (2006), 24, 283-290 [5], E. Vasina, V. Vatulin (VNIIEF, Sarov). Experimental Scheme for Investigation of Ion Stopping in Plasma-Indirect Laser Target Design. GSI-2000-2 Report June 2000, p.52, www.gsi.de

58 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 58 c Abstracts - oral presentations )

Th-9. Multiterrawatt peak power generated by the all diode pumped laser - POLARIS J. Hein, R. Bodefeld, S. Podleska, M Hornung, A. Savert, A. Kessler, M. Wolf, S. Keppler, M. Nicolai, M. Schnepp, J. Korner, M.C. Kaluza, G.G. Paulus Helmholtz Institute Jena, Institute of Optics and Quantum Electronics, Friedrich Schiller University Jena, Germany

We report on the design and construction of the fully diode pumped ultrahigh peak power laser system POLARIS at the Friedrich Schiller University and the Helmholtz Institute Jena, Germany. Presently, this laser system reaches a peak power of several tens of terawatt. The last ampli_er, which will boost the output energy to the 100-J level, is nearly completed and will be soon commissioned. The applied technology and the basic design are reviewed.

Th-10. Intense ions for high energy density in matter research Alexander Golubev Institute for Theoretical and Experimental Physics (ITEP), Russia.

Investigation of high energy density phenomena in the laboratory offers the advantage of controlled and reproducible conditions. Lasers, pulsed power machines, high explosives and intense particle beams from accelerators are commonly used to generate high energy density states. Among these techniques heavy ion beams are relatively new. Intense heavy-ion beams are excellent tool to generate uniform large-volume plasmas with solid state density. The energy deposition of ion beams into a non-ionized target is a reasonably well understood process and direct heating of a well-defined extended volume is achieved by a rather homogeneous energy deposition. High precision experiments to study the properties of bulk matter require a detailed knowledge about the exact amount of energy deposited into the sample as well as the spatial and time distribution of the energy inside the target volume. This demand is intrinsically fulfilled by the very nature of the interaction processes of heavy ions with matter themselves. The highest energy deposition occurs at the end of the range. This regime is commonly called the Bragg peak and its position is precisely determined by the total ion energy. Higher beam energy would cause the Bragg peak to shift out of the target. In this case the target is heated in a very homogeneous manner. If the ion beam is intense enough, the beam heated target volume is transformed into dense plasma. Thus intense ion beams open new opportunities to investigate the interaction phenomena of heavy ion beams with dense plasma and they allow to study the hydrodynamic and radiative properties of beam heated matter with high precision experiments, and improved or complementary techniques. In order to achieve this ambitious goal it is also necessary to include the development of new diagnostic techniques and the design of appropriate heavy ion targets. The heavy ion synchrotrons ITEP-T WAC at ITEP, Moscow and SIS 18 at the Gesellshaft fur Schwerionenforschung (GSI), Darmstadt, are unique facilities which deliver intense beams of different heavy ion species. These beams have enabled important research in the field of HED matter during last years. GSI has proposed the construction of a new synchrotron ring SIS 100, which will deliver a heavy ion beam with a much higher intensity than the upgraded SIS18 and ITEP-TWAC facilities. The new facility with the 100 Tm heavy-ion synchrotron and a bunch compression system for the generation of very intense short ion bunches below 50 ns pulse length will extend the available beam deposition power from the current level of 50 GW/g by more than two orders of magnitude up to 12,000 GW/g. This will open up unprecedented opportunities for the production of ion beam heated and/or compressed plasmas.

59 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Th-ll. Coherent beam combination of wave-front divided 4 beams by phase controlled stimulated Brillouin scattering phase conjugation mirrors toward the realization of a practical laser fusion driver H. I. Kong1. J. S. Shin1, S. Park1, S. Cha1, and Y. S. Kim2 'Department of Physics, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea 2Department of Electrophysics, Dankook University, 29 Anseo-dong, Cheonan, Choongnam 330-714, Republic of Korea

Creating a laser with a high power and high repetition rate is challenging due to thermal problems related to the laser medium. Several studies have sought to overcome these problems [1,2] but the suggested solutions are inadequate for certain applications, such as a laser fusion driver for practical power generation, because of thermal problems with the laser media. A beam combination method can fundamentally solve the thermal problems because it uses only small-size amplifiers and coherently combines the beams to create a high-power laser. The beam combination laser using stimulated Brillouin scattering phase conjugate mirrors (SBS-PCMs) is a promising technique for this purpose [3,4]. The SBS-PCM generates a phase conjugate beam which can restore the optical distortions generated by active media in beam path. However, because the SBS process is initiated from thermal noise in the SBS medium, the relative phases between the separate SBS-PCMs are inherently random. With a "self-phase control" method, any number of beams can be reflected from each SBS-PCM with definite relative phases. The self-phase control method was demonstrated experimentally [5] and expanded to control the relative phases of the beams. We report on the experimental results of combining four beams by using SBS-PCMs with wave-front division. After passing through a four-beam aperture, the beams are combined with the aid of the SBS-PCMs. An interference pattern is generated between a part of the combined output beam and a part of one of the expanded beams, Beam 1. The relative phases are calculated from this interferogram. The output energy was 169 mj ± 6 mj when the input energy was 32.2 mj ± 0.3 mj. The standard deviations of the phase differences of beams 2, 3, and 4 were measured to be A/26.5, A/28.0, and A/26.1, respectively. Acknowledgments This work was supported by a grant from the Nuclear Research and Development Program of the Korea Science and Engineering Foundation, which is funded by the Korean government (MEST) (grant code: M20090078160). It was also supported by the R&D Program through the National Fusion Research Institute of Korea (NFRI) funded by the Government funds, the KAIST High Risk High Return Project, and the International Atomic Energy Agency as a part of the coordinated research project "Pathway to Energy from Inertial Fusion - An Integrated Approach" (Research Contract No. 13758/R0). References [1] S. A. Payne et al., J. Fusion Energy 17, 213 (1998). [2] C. L. Olson, et al., IAEA-TECDOC-1466 (2005). [3] H. J. Kong, J. S. Shin, D. H. Beak and S. Park, J. Korean Phys. Soc. 56, 177 (2010). [4] H. J. Kong, J. W. Yoon, J. S. Shin, D. H. Beak and B. J. Lee, Laser Part. Beams 24, 519 (2006). [5] H. J. Kong, S. K. Lee, D. W. Lee, and H. Guo, Appl. Phys. Lett. 86,051111 (2005).

Th-12. Electron beams accelerated with two TW class lasers: preplasma effect of target materials M. Gerbaux1, F. Gobet1, M. Tarisien1, F. Hannachi1, E.d'Humieres2, A. Debayle3, P. Nicolai2, V. Tikhonchuk2, G. Malka2, M.M. Aleonard1 1 Universite Bordeauxl, GNRS-IN2P3,Centre d'Etudes Nucleates de Bordeaux Gradignan, CENBG,Chemin du Solarium, 33175 Gradignan, France. 2 CELIA, Universite Bordeauxl, 351 Cours de la Liberation, 33405 Talence, France

It is well known that ultra short pulses of UHI lasers in the TW domain can produce energetic electrons above 10 MeV. For nuclear physics purposes the range 10-100 MeV is well appropriate to explore (g,xn) reactions.

60 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 60 c Abstracts - oral presentations

These reactions are of interest, in particular, to study the production of isomers in plasma in relation with astrophysical problems [1], Meanwhile a careful study of the produced photons is of interest for the study of intense photon "beams" (radiography, ignition in the Inertial Fusion physics). In both cases, the optimization of these photon beams as regards the number of photons as well as their angular dispersion is important. From previous experiments, with polypropylene targets, it has been shown that both the target thickness and the preplasma conditions influenced the distributions of the produced electrons [2,3]. Here we investigate the effect of the target atomic number (Z) on the electron production. The experiments have been done with two TW class lasers, with fs pulses; targets of CH, Al Cu, Au and Ta have been used. All the targets had the same thickness (10pm). The energy distribution of the electrons and their angular distribution have been characterized [4], Both lasers had nearly the same energy (1J), the pulse duration was respectively 40 and 80 fs, respectively at LOA (Palaiseau) and IOQ (Iena). The main differences of the lasers regarded the contrast (106 at LOA, 107 at IOQ) and the ASE duration (2 ns or 0.5ns). In presence of a large ASE the number of electrons above 10 MeV were ~109, roughly 3 orders of magnitude higher than without ASE. As regards the angular dispersion of electrons above lOMeV,measured at LOA, it was increasing progressively between CH targets and Au ones, ranging from 12° to 40° between these increasing atomic numbers. The explanation of such a flagrant difference in the results of these two apparently similar experimental campaigns is related to the size and form of preplasma created by the ASE preceding the main pulse. Namely, in the first series of experiments with low Z targets the ASE creates a large scale plasma that expands spherically from the laser focal spot. The characteristic density scale length is much larger than the laser focal spot and consequently the main pulse interacts essentially with a weakly inhomogeneous low density plasma. These conditions are very favorable for the efficient electron acceleration and a formation of a collimated electron beam. On the contrary, in the second series of a weaker ASE, or in the experiences with higher Z targets, the size of preplasma is comparable or even smaller than the focal spot size. Consequently, the efficiency of acceleration is much lower and the beam divergence is much higher due to the density curvature radius comparable to the focal spot. Hydrodynamic simulations of the ASE interaction with the targets and the kinetic PIC simulations of electron acceleration have confirmed this assertion. Acknowledgments: We acknowledge the Conseil Regional dAquitaine, IN2P3/CNRS, the Institut Laser Plasma and LaserLab for financial supports during experiments as well as LOA and IOQ laser staff help. References [1] F. Hannachi et al., Plasma Phys. Control Fusion 49, B79-B86 (2007). [2] G. Malka et al., Phys. Rev. E 66, 066402 (2002). [3] C. Courtois et al., Phys. of Plasma 16, 013105 (2009). [4] M. Gerbaux et al., RSI 79, 023504 (2008).

Th-13. Energy relaxation in dense laser-produced two-temperature plasmas M. Schlanges1, Th. Bornath2, J. Vorberger3, D.O. Gericke3 'Institutfur Physik, E.-M.-Arndt-Universitat Greifswald, 17489 Greifswald, Germany 2Institutfur Physik, Universitat Rostock, 18051 Rostock, Germany 3CFSA, Department of Physics, University of Warwick, Coventry CV4 7AL, UK

The creation of states with high energy density in the laboratory requires a large and fast energy input into matter like in dynamic experiments applying intense particle beams or lasers to heat and compress the material under investigation. Inevitably, highly nonequilibrium states are produced with the energy being pumped mainly into either the ion or the electron subsystem. Apart from the hydrodynamic response, temperature equilibration takes the longest of all relaxation processes and, thus, defines the minimum time delay between pump and probe pulses needed for equilibrium measurements. In the present contribution, general energy balance equations for multicomponent systems are derived on the basis of quantum kinetic theory. This approach allows for a consideration of correlations in both the internal

61 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations ) energies and the energy transfer rates. We show how known expressions for the energy transfer rates, namely, the Fermi-Golden-Rule (FGR) and Coupled Modes (CM) rates, follow from the presented formalism. It is shown that these rates describe the transfer of total energy between the subsystems and the approximations made are highlighted. As the effects of coupled collective modes are still under discussion, we present results for the electron-ion energy transfer rates. Then the equilibration of all contributions of the total energy including the species temperatures is investigated for dense hydrogen and beryllium relevant for inertial confinement fusion as an example. We find deviations from an ideal temperature relaxation and demonstrate how correlations and collective modes affect the shape of the temperature curves, the relaxation time, and the final temperature. It turns out that the most important effect of coupled modes is not an increase in relaxation time but a different form of the time evolution of the electron and ion temperatures, while correlations mainly affect the final plasma temperature. Finally, a comparison with experimental results and recent molecular dynamics (MD) simulations is given. Acknowledgements This work was supported by the Deutsche Forschungsgemeinschaft via SFB 652 and the Engineering and Physical Sciences Research Council of the United Kingdom (EP/D062837). References [1] ]. Vorberger and D.O. Gericke, Phys. Plasmas 16, 082702 (2009). [2] M. Schlanges, Th. Bornath, J. Vorberger, D.O. Gericke, Contrib. Plasma Phys. 50, 64 (2010). [3] J. Vorberger, D.O. Gericke, Th. Bornath and M. Schlanges, Phys. Rev. E 81,046404 (2010).

Fr-1. Effects of preplasma on hot electron coupling and propagation in cone attached wire targets T. Ma*. P. K. Patel, M. H. Key, D. J. Larson, C. D. Chen, L. Divol, D. Hey, A. J. Kemp, S. Le Pape, A. J. Mackinnonj A. G. MacPhee, H. S. McLean, Y. Ping, S. C. Wilks Lawrence Ttvermore National Laboratory, Livermore, CA, U.S.A. D. P. Higginson, H. Sawada, T. Yabuuchi, M. S. Wei, F. N. Beg University of California, San Diego, La Jolla, CA, U.S.A. K. U. Akli, R. B. Stephens General Atomics, San Diego, CA, U.S.A. R. R. Freeman, G. E. Kemp, A. G. Krygier, L. D. Van Woerkom The Ohio State University, Columbus, Ohio, U.S.A. R. Fedosejevs, H. Friesen, Y. Y. Tsui University of Alberta, Edmonton, Alberta, Canada S. D. Baton, M. Koenig, F. Perez Laboratoire pour I'Utilisation des Lasers Intenses, Ecole Polytechnique, France

The reentrant cone approach to Fast Ignition remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. A few of the imperative issues facing Fast Ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This talk will discuss results from an experiment on the Titan Laser at LLNL (150 J, 0.7 ps, 2X1020 W/cm2) where laser prepulse was intentionally varied from 8 mj (the minimum, intrinsic prepulse of the short pulse beam) up to 1000 mj by using a separate long pulse (3 ns) beam to artificially simulate prepulse by overlapping the main prepulse in both space and time. The targets were 30° opening angle Au cones with a 20 mm thick wall, 10 mm thick tip, and 30 mm inner diameter, with a 40 mm-diameter, 1.5 mm long Cu wire attached at the cone tip. The Cu wire served as a Ka fluorescence diagnostic to measure forward-propagating electrons out of the cone tip. A highly oriented pyroMc graphite (HOPG) spectrometer provided absolute Ka yields and a spherical Bragg reflecting crystal recorded the spatial pattern of Ka emission.

62 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

From these two diagnostics, a reduction in coupling of a factor of 8 was observed when prepulse was increased from 8 mj to 1000 mj. The 3D hybrid transport code Zuma has been used to infer the initial electron distribution

(Th and conversion efficiency into hot electrons) by matching the fall-off of the Ka emission along the length of the wire. The rad-hydro code, HYDRA, was used to model the evolution of the plasma in the cone. Results will also be presented from work using a PIC-Hybrid code to model the full-scale laser interaction, electron generation, and transport in a cone wire target. Acknowledgements This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and supported by the Department of Energy under contracts DE-FC02-04ER54789 (Fusion Science Center) and DE-FG-02-05ER54834 (ACE). T. Ma is funded through the Lawrence Scholar Program.

Fr-2. High-energy laser astrophysics with anti-matters produced with ultra-intense lasers - theory, computation, scaling, experimental data and high-energy astrophysics model experiment Hideaki Takabe ILE, Osaka University takabe@ile. osaka-u. ac.jp

With the maturity of high-power laser technology, we can realize an extremely high intensity of photons in a tiny space. About 10 kj of leV photons (1022photons) can be squeezed in a space of several micro mater during 10 fs (10 14 s). This means the density of photons of 1034/cm3. Photon is boson and can be squeezed to a tiny space. We expect that we can design unique experiments of the collective effects of elementary particles and such lasers can also be used for a new type of experiments. The physics will be wider with the combination of the conventional accelerators. I briefly describe what we have carried out as academic research related to high energy astrophysics. One is the possibility of laboratory high-energy astrophysics experiment with use of the electron-positron plasma produced by laser irradiation on high-Z material [1], Regarding the electron-positron plasma, we had started the analysis of the experimental data obtained by Tom Cowan et al [2], It was around the year of 2000. We have carried out a computational simulation of the positron production based on the Fokker-Planck type kinetic equation [3]. In such a situation, most of the laser energy is converted to the energy of relativistic electrons, while it was found that the direct production of the positrons via the Trident process is relatively in- efficient. The most of positrons are found to be produced, however, via Bethe-Heitler process. In this process, the electron energy is once converted to that of y-ray via bremmstralung process and y-ray efficiently produces the pairs via interaction with nuclei[3]. In the later work, we found that the plasma effect through the am- bipolar electric field is found to be essential in comparing with the Cowans experimental data[4]. With the promising, recent experimental results[5], I will explain the physics of positron production and modeling high- energy astrophysical plasma with experimental pair plasmas. References [1] H. Takabe, Progress of Theoretical Physics, Supplement No. 143, PP. 202-265 (2001). [2] T. E. Cowan et al., Laser Part. Beams 17, 773 (1999). [3] K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505-1512 (2002). [4] H. Takabe, Nuclear and Particle physics with Ultra-Intense Lasers, to be published(2010). [5] H. Chen, S. C. Wilks, et al, Phys. Rev. Lett. 102,105001 (2009); H. Chen, S. C. Wilks, et al, Phys. Plasmas . 16, 122702 (2009)

63 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Fr-3. Extreme state of matter physics at FAIR Boris Sharkov FAIR/HC GSI, Planckstr. 1, 64291 Darmstadt, Germany.

The Facility for Antiproton and Ion Research in Europe, FAIR, will provide worldwide unique accelerator and experimental facilities allowing for a large variety of unprecedented fore-front research in extreme state of matter physics and applied science. Indeed, it is the largest basic research project on the roadmap of the European Strategy Forum of Research Infrastructures (ESFRI), and it is cornerstone of the European Research Area. FAIR offers to scientists from the whole world an abundance of outstanding research opportunities, broader in scope than any other contemporary large-scale facility worldwide. More than 2500 scientists are involved in setting up and exploiting the FAIR facility. They will push the frontiers of our knowledge in hadron, nuclear, atomic and applied physics far ahead, with important implications also for other fields in science such as cosmology, astro and particle physics, and technology. It includes 14 initial experiments, which form the four scientific pillars of FAIR. The main thrust of intense heavy ion and laser beam-matter interaction research focuses on the structure and evolution of matter on both a microscopic and on a cosmic scale. This presentation outlines the current status of the Facility for Antiproton and Ion Research. It is expected that the actual construction of the facility will commence in 2010 as the project has raised more than one billion euro in funding. The sequence and scope of the construction will be described. Also the physics program of FAIR, based on the acquired funding, will be presented Reference: www.gsi.de/fair/

Fr-4. Ion beam heating for fast ignition S.Yu. Gus'kov1. D.V. Il'in2, J. Limpouch3, O.Klimo3, V.E. Sherman2 'P.N. Lebedev Physical Institute, Russian Academy of Science, Leninski pr.53, Moscow, 119991 Russia 2St. Petersburg Institute of Machine Building, Polyustrovski pr.14, St. Petersburg, 195197 Russia 3Czech Technical University in Prague, Zikova 4, 16636, Prague 6, Czech Republic

The characteristics features of the formation of the spatial distribution of the energy transferred to the plasma from a beam of ions with different initial energies, masses and charges under fast ignition conditions [1,2] are determined. The notion of the Bragg peak is extended with respect to the spatial distribution of the temperature of the ion-beam-heated medium. The parameters of the ion beams are determined to initiate different regimes of fast ignition of thermonuclear fuel precompressed to a density of 300-500 g/cm3 - the edge regime, in which the ignition region is formed at the outer boundary of the fuel, and the internal regime, in which the ignition region is formed in central parts of the fuel. The conclusion on the requirements for fast ignition by light [3,4] and heavy [1,5] ion beams is presented. It is shown that the edge heating with negative temperature gradient is described by a self-similar solution. Such a temperature distribution is the reason of the fact that the ignited beam energy at the edge heating is larger than the minimal ignition energy by factor 1.65. The temperature Bragg peak may be produced by ion beam heating in the reactor scale targets with pR-parameter larger than 3-4 g/cm2. In particular, for central ignition of the targets with pR-parameter in the range of 4-8 g/cm2 the ion beam energy should be, respectively, from 5 to 7 times larger than the minimal ignition energy. The work by S.Yu. Gus'kov, D.V. Il'in, and V.E. Sherman was supported by the Ministry of Education and Science of the Russian Federation under the program "Development of the Scientific Potential of High Education for 2009-2010" (project no. 2.1.1/1505) and the Russian Foundation for Basic Research (project no. 08-02-01394_a). The work by ]. Limpouch and O.Klimo was supported by the Czechian Ministry of Education (projects nos. LC528, MSM6840770022).

64 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

References [1] N. G. Basov, S. Yu. Gus'kov, L. P. Feoktistov, J. Soviet Laser Research 13, 396 (1992) [2] M. Tabak, J. Hammer, M. E. Glinsky et al., Phys. Plasmas 1,1626 (1994) [3] S.Yu. Gus'kov, Quantum Electronics 31, 885 (2001) [4] M. Roth, T.E. Cowan, M.H. Key et al., Phys. Rev. Lett. 86, 436 (2001) [5] A. Caruso and V.A. Pais, Nuclear Fusion 36, 745 (1996)

Fr-5. LASERIX: an open facility for developments of soft X-ray and EUV lasers and applications D. RosH S. Kazamiasu, O. Guilbaud1'2, K. Cassou1'2 S.Daboussi1, M. Pittman2, J.-C. Lagron1'2, B. Cros1'2, G. Maynard2 'LPGP, Bat 210, Universite Paris-Sud / CNRS, Orsay, France 2LASERIX, Centre Laser Universite Paris-Sud-LUMAT, France

LASERIX is a high-power laser facility designed to produce High-repetition-rate XUV laser beams pumped by a Titanium-.Sapphire laser. The objectives are to develop soft X-ray lasers (SXRL) at various wavelengths and use them for applications. The facility is based on a titanium-doped sapphire (Ti:Sa), delivering pulse energy of 2 J at 10 Hz repetition rate at the exit of the front-end and 40 J before compression at 0.1 Hz repetition rate (using a Ti:Sa crystal amplifier of 10 cm in diameter). The large width of the Ti:Sa spectrum opens the way to short pulses and to new SXRL schemes. Thus, LASERIX will provide the opportunity to study a large variety of SXRL schemes beside the conventional "transient collisional" one (OFI pumping, inner shell X-ray lasers,...). The 40-J beam will be basically divided in two parts that can be independently compressed, resulting in two beams of 10 J with a pulse duration which is continuously tunable between 40 fs and 500 ps. Three different EUV and soft x-ray beam lines will run simultaneously: An EUV DGRIP/GRIP laser line at 10Hz, a femtosecond EUV high order harmonic laser line at 10Hz and a high energy soft x-ray laser line at 0.1Hz. This configuration highly enhances the scientific opportunities of the facility. Indeed it will be possible to perform both Soft X-ray laser experiments and more generally pump/probe experiments, mixing IR and EUV sources. Thus, this facility will provide to users opportunities for a large range of Laser Interaction with Matter investigations. In this contribution, the main results concerning both the development of EUV and soft x-ray laser sources and their use for scientifical applications will be presented. Finally, we will indicate the perspectives of the LASERIX facility in the near future, especially taking into account the national (Institut de la Lumiere Extreme: ILE project, laboratories working on the development of the XUV sources) and international (Extreme Light Infrastructure project) contexts.

Fr-6. Stochastic heating in high intensity laser-plasma interaction. Application to the wake field acceleration process A. Bourdier. M. Drouin CEA, DAM, DIF, 91297 Arpajon Cedex, France

Recently, PIC simulations results published by Tajima et al. and Sheng et al. have shown that chaos can play an important role in the efficient electron heating observed in laser-plasma interaction at very high intensities. These results led us to investigate the condition under which significant stochastic heating is likely to take place. First, we shall consider the dynamics of a single charged particle in the field of a high intensity wave propagating in an unmagnetized vacuum or plasma. In a second part, the effect of a constant homogeneous

65 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations 3 magnetic field will be discussed. Third, in the case of a plasma interacting with several electromagnetic waves, the use of Chirikov's criterion to predict the conditions favouring stochastic heating will be presented. The role of chaos in the acceleration of an electron interacting with two counterpropagating waves in the direction of propagation of the high intensity wave will be discussed. Finally, it will be shown that when considering a low density plasma interacting with a high intensity wave perturbed by a low intensity wave, stochastic heating (or acceleration) can provide electrons with the right momentum for trapping in the wake field and efficient acceleration. References [5] Dynamics of a charged particle in progressive plane waves: stochastic acceleration. Application to the Wake Field. Acceleration Process, IEEE Transactions on Plasma Sciences, Vol.38., 728 (2010). [6] Dynamics of a charged particle in progressive plane waves propagating in vacuum or in plasma. Stochastic acceleration. Laser and Particle Beams, Vol.27 (2009). [7] Dynamics of a charged particle in a progressive plane wave. Physica D, Vol.138, 226 (2009). [8] Stochastic heating in ultra high intensity laser-plasma interaction. Laser and Particle Beams, Vol.25 (2007). [9] Stochastic heating in ultra high intensity laser-plasma interaction. Physica D, Vol.206 (2005).

Fr-7. Accurate offline dispersion measurement of Petawatt-class chirped pulse amplification compressor and stretcher systems C. Haefner*, J. Crane, J. Halpin, J. Heebner, V. Kanz, H. Phan, J. Nissen, M. Shverdin, R. Hackel, J. Dawson, M. Messerly, and C. W. Siders Lawrence Livermore National Laboratory, L-470, 7000 East Ave., Livermore, CA 94551, USA *[email protected]

The Advanced Radiographic Capability (ARC) on the National Ignition Facility (NIF) is designed to produce energetic x-rays in the range of 10-100 keV for backlighting NIF targets. ARC will convert 4 of the 192 NIF beamlines into 8 split beams, delivering laser pulses with adjustable pulse durations from 1 ps to 50 ps at the kilo-Ioule level. Adjustable time delays between the 8 beams enable X-ray "motion-picture" capture with tens- of-picosecond resolution during the critical phases of an ICF shot. The precise alignment of stretcher-compressor pairs in energetic chirped pulse amplification (CPA) systems is tedious and requires several iterations using advanced temporal diagnostics until the shortest pulse durations and highest peak intensities are achieved. For large, energetic Petawatt laser systems with beam sizes up to 40 cm, diffraction gratings in the compressor reach meter-scale size and are difficult to precisely align. We developed a group delay diagnostic which enables accurate, offline measurements of highly dispersive components such as stretchers or compressors with sub-picosecond accuracy. This diagnostic tool enables us to simply measure each dispersive component offline, and balance the dispersion in each beamline. Furthermore it allows exactly matching the dispersion of ARC'S eight, independent four-grating compressors, which is critical for producing eight identical pulses. ARC utilizes a unique, folded compressor design for maximum compactness; two 5.5m long vacuum vessels house 8 compressors with 91cm x 45cm multilayer, dielectric gratings. The group delay diagnostic utilizes the phase-shift technique for measuring the dispersion characteristics of each individual element, e.g. grating stretcher, chirped fiber Bragg grating, grating compressor, material dispersion, or an entire laser system. The system uses an amplitude modulated, highly-stable, single-frequency laser, which is scanned over the spectral bandpass of the system under test. The amplitude modulation generates sidebands at fm=l-6 GHz, which is detected with a fast photodiode. Using a network analyzer, we measure the phase difference of the modulation-signal, A0(vm) between the input and the output detectors as we scan the laser over the spectral pass band of the dispersive system under evaluation. The group-delay can then be derived from the phase difference divided by the modulation frequency. Using the Treacy formalism we can calculate the angle of incidence and slant distance from the group delay curve at a higher precision than what

66 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations 3

physically can be measured. We have achieved a group delay measurement precision of better than 100 fs, exceeding the ARC requirement of ±0.5 ps, and which is currently limited by the network analyzer precision and the maximum modulation frequency. In this talk we will describe the dispersion management strategy on ARC, and present the results obtained on the ARC injection laser system test-bed, which utilizes the ARC architecture up to the Joule level. Using this technique we achieved 1.3J, 1.02 Terawatt with only one iteration-step, equivalent to 78% temporal Strehl ratio. Acknowledgement: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

Fr-8. Validation experiments on laser radiation transmission through nearcritical plasma with several spatial scales N.G. Borisenko1, Yu.A. Merkuliev1, J. Limpouch2, C. Labaune3, S. Depierreux4, V.T. Tikhonchuk5, V.G. Pimenov6 ' Lebedev Physical Institute, 53 Leninskiy pr., Moscow, 119991, Russia 2 FNSPE, Czech Technical University in Prague,115 19 Prague 1, Czech Republic 3 Institute Laser & Plasmas, TALENCE cedex, France 4CEA/DIF, BP 12, 91680 Bruyeres-le-Chatel, France 5 CELIA, University Bordeaux 1, 351 cours, 33405, Talence cedex, France 6 Zelinsky Institute of Organic Chemistry, Moscow, 119991 Russia

One of the examples of "validation experiments" was the international collaboration experiments on laser radiation smoothing using foam-layer [1-3] which demonstrated correct idea, but new disadvanced effects were obtained: 1. Preheating of foil (shell-container surface model) 2. Laser radiation transmission through microheterogeneous plasma and polymer aerogel 3. Wave-like radiation transparency (oscillation) Spatial and temporal uniformity of preheating and laser radiation transmission need for experimental verification. References [1] C. Labaune, S. Depierreux, V.T. Tikhonchuk, P. Nicola'i, C. Stenz, M. Grech, T. Michel, D. Pesme, N.G. Borisenko, J. Limpouch, W. Nazarov. Laser plasma smoothing studies with the LIL facility. // Inertial Fusion: Science and Application, Kobe, Japan, 9-14 September 2007, W02.4 [2] J. Limpouch, P.Adamek, N.G.Borisenko, N.N.Demchenko, T.Kapin, M.Kalal, A.M.Khalenkov, D. Klir, VKmetik, E.Krousky, M. Kucharik, R.Liska, K.Masek, W.Nazarov, M.Pfeifer, M.Sinor, J.Ullschmied. Impact of Foam Structure and Composition on Absorption and Energy Transfer. // 33rd EPS Conference on Plasma Phys. Rome 19-23 June 2006, ECA Vol. 301, P-5.001 (2006). [3] S. Depierreux, C. Labaune, D.T. Michel, C. Stenz, P. Nicolai, M. Grech, G. Raizuelo, S. Weber, V.T. Tikhonchuk, P. Loiseau, N.G. Borisenko, W. Nazarov, S Huller, D. Pesme, M Casanova, J. Limpouch, C. Meyer, P. Di-Nicola, R. Wrobel, E. Alozy, P. Romary, G. Thiell, G. Soullie, C. Reverdin, B. Villette. // Laser Smoothing and Imprint Reduction with a Foam Layer in the Multikilojoule Regime. // Physical Review Letters, 102,195005, (2009).

67 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Fr-9. Intense femtosecond laser filamentation science in air S. L. Chin Center for Optics, Photonics and Laser (COPL) Laval University Quebec City, Quebec G1V0A6 Canada

Universal phenomena inside the filament core of a femtosecond Ti-sapphire laser pulse in air will be discussed. These include birefringence induced by the strong field inside the filament through cross-phase modulation in the otherwise isotropic air, intensity clamping prohibiting reaching very high intensity whatever one does, molecular alignment and the revival of rotational wave packets as well as population trapping (stabilization). This trapping phenomenon is believed to be a missing universal process in intense laser interaction with atoms and molecules. Super-excited states of molecules are observed which are proposed for the first time to be the trapped Rydberg and/or highly excited states in the continuum.

Fr-10. Interaction of energetic ions with high-density plasmas P.O. Gericke, D. Edie, A. Grinenko and J. Vorberger Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom

The talk will review the importance of energetic ions in different inertial confinement fusion scenarios: i) heavy ion beams are very efficient drivers that can deliver the energy for compression in indirect as well as direct drive approaches; ii) the interaction of a-particles, that are created in a burning plasma, with the surrounding cold plasma is essential for creating a burn wave; iii) laser-produced ion beams are also a strong candidate to create the hot spot needed for fast ignition. In all applications the ions interact with dense matter that is characterized by strongly coupled ions and (possibly) partially degenerate electrons. Moreover, the coupling between beam ions and target electrons can be strong as well. Under these conditions, standard approaches for the beam- plasma interactions process are known to fail. The presentation will demonstrate how advanced models for the energy loss of ions in dense plasmas can resolve the issues mentioned above. These models are largely built on quantum kinetic theory that is able to describe degeneracy and strong coupling in a systematic way. In particular, strong interactions require a quantum description for electron-ion collisions in dense plasma environments, which is done by direct solutions of the Schrodinger equation. Degeneracy and collective excitations can be included via the Lenard- Balescu description where strong interactions may be included via a pseudo-potential approach. Finally, results are shown for all three fusion applications described above. The effects related to strong coupling and degeneracy mainly concern the end of the stopping range where the beam ion does not have enough energy to excite all possible degrees of freedom and, thus, certain processes are frozen out. However, we also find a significant reduction of the range for swift heavy ions in the GeV-range when stopping in dense matter is considered. The stopping range of a-particles in the highly compressed matter around the burning fusion core is however strongly increased due to degeneracy of the target electrons. This result implies the need for much larger hot spots than predicted by standard models. Similarly, the range of light ions considered for fast ignition is increased. This makes success of this efficient ICF approach harder to achieve, but already reflects the need for larger hot spots due to the larger spread of the a-particles heating. Acknowledgements: This work is funded by the Engineering and Physical Sciences Research Council of the UK.

68 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Fr-ll. Attosecond pulse generation in noble gases in the presence of extreme high intensity THz pulses E. Balogh1. J. A. Fiilop2, J. Hebling2, P. Dombi3, G. Farkas3, K. Varju4 'Department of Optics and Quantum Electronics, University of Szeged, 6720 Szeged ,Dom ter 9. Hungary department of Experimental Physics, University of Pecs, 7624 Pecs, Ifjusag u. 6. Hungary 3Research Institute for Solid-State Physics and Optics, 1121 Budapest, Konkoly-Thege M. lit 29-33, Hungary ''HAS Research Group on Laser Physics, University of Szeged, 6720 Szeged, Dom ter 9. Hungary

The shortest - attosecond - light pulses available today are produced by high harmonic generation (HHG) of near-infrared (NIR) laser pulses in noble gas jets [1,2], providing a broad spectral plateau of XUV radiation ending in a cutoff. The minimum pulse duration is determined by the achievable bandwidth (i.e. the position of the cutoff), and the chirp of the produced pulses. The extension of the cutoff by increasing the laser intensity is limited by the depletion and phase matching problems of the medium. An alternative method demonstrated to produce higher harmonic orders is by using longer pump pulse wavelength, with the disadvantage of decreased efficiency [2], Recently it was shown that application of a quasi-DC high strength electric field results in an increase of more than a factor of two in the order of efficiently generated high harmonics [3]. However, the possibility to implement the method proposed in [3] of using a C02 laser to create a quasi-DC field for assisting HHG of the NIR laser is questionable, because it's technically very challenging to synchronize pulses from different laser sources. Alternatively, synchronous production of THz pulses with the NIR laser pulse offers a more promising route. The first numerical test of this idea has been reported in [4]. In this contribution we further investigate the method for realistic THz field strengths and short driving pulses, exploring the effect of longer pump laser wavelength on the process. We assume the presence of high intensity THz pulses for supplying the high-strength quasi-DC electric field. The spectrum as well as the chirp of the produced radiation is calculated. We use the non-adiabatic saddle point method to determine the generated radiation described in [6]. We simulate harmonic generation in noble gas atoms, with few cycle NIR pulses of peak intensity at and above 2xl014 W/cm2 (388 MV/cm) and wavelengths 800 nm and 1560 nm. The THz field strength is varied from 0 to 100 MV/cm (the highest field strength currently available [5]). The generated spectra is calculated for each half-cycle, and coherently summed. As a result of the presence of the THz field, the half-cycle periodicity of the HHG process is broken, leading to the appearance of both odd and even harmonics and a radiation with a spectrum split to two plateaus. The two cutoffs are set by the radiation produced in the consecutive half-cycles. The higher cutoff increases, whereas the lower cutoff decreases with increasing THz field strength. In cases when THz field is added to a few cycle laser pulse a broad super-continuum part in the spectra can be obtained. The broad spectrum of the produced radiation would support the synthesis of single attosecond pulses in the absence of a strong chirp. The method presented here allows for the production of a broader spectral range of harmonics, leading to the synthesis of even shorter attosecond pulses. References [ 1 ] Gy. Farkas and Cs. Toth, Phys. Lett. A 168,447 (1992). [2] F. Krausz and M. Yu. Ivanov, Rev. Mod. Phys. 81, 163 (2009). [3] Y. Xiang, Y. Niu, S. Gong, Physical Review A 79,053419 (2009). [4] W. Hong, P. Lu, P. Lan, Q. Zhang, X. Wang, Optics Express 17, 5139 (2009) [5] A. Sell, A. Leitenstorfer, and R. Huber, Optics Letters 33, 2767 (2008). [6] G. Sansone, C. Vozzi, S. Stagira, and M. Nisoli, Phys. Rev. A 70,013411 (2004)

69 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Fr-12. Few-cycle surface plasmon enhanced electron acceleration Peter Racz', Miklos Lenner1, Norbert Kroo1, Gyozo Farkas1, Takao Fuji2, Ferenc Krausz2, Scott E. Irvine3, Abdul Y. Elezzabi3 and Peter Dombi1 1 Research Institute for Solid-State Physics and Optics, Budapest, Hungary 2Max-Planck-Institut fur Quantenoptik, Garching bei Munchen,Germany 3Ultrafast Photonics and Nano-optics Laboratory, University of Alberta, Edmonton, Canada

It is possible to generate high-quality ultrafast electron beams with keV energy based on surface plasmon- enhanced electron acceleration [1-3]. The beam generated this way can be also used to investigate ultrafast phenomena in the plasmon field. For the better undersanding of the temporal behavior of these ultrafast surface processes we carried out time-resolved experiments with 5.5 fs laser pulses for the first time. In this experiment, we executed an autocorrelation measurement with an ultra-broadband interferometer. By generating surface plasmons at the output of the interferometer, we measured the plasmonic photocurrent as a function of the delay between the interferometer arms. Figure (a) shows a typical measuared result, and figure (b) shows the fourth order calculated autocorrelation function of the 5.5 fs long laser pulse, corresponding to the fourth order nonlinearity of the electron emission process. According to the correspondence of these two curves, we can also state that the length of the generated surface plasmon pulse is only 2-3 optical cycles.

(b)

J L -20 -10 0 10 20 -20 -10 0 10 20 delay (fs) As a further exeperiment, we executed spectrally resolved measurements of the electron beam at higher intensities. According to these results, it is possible to reach electron beams with keV energy in the few-cycle regime too. It was found that the field strength of the surface plasmons is X7... X30 higher than that of the focused laser pulse. [1] S. E. Irvine, A. Dechant, A. Y. Elezzabi, Phys. Rev. Lett. 93,184801 (2004). [2] S. E. Irvine, P. Dombi, G. Farkas and A. Y. Elezzabi, Phys. Rev. Lett. 97,146801 (2006). [3] P. Dombi & P. Racz, Opt. Express 16, 2887 (2008). [4] P. Dombi et al., submitted (2010).

70 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - oral presentations )

Fr-13. Ka emission of copper foil targets driven by an ultrashort laser pulse at relativistic regime WEI HONG'. WENGZHONG HUANG, XIANGXIAN WANG, WEIMIN ZHOU, FENG HU, YINGLIN HE, TIANSHU WEN, DONGXIAO LIU, XIAODONG WANG, XIAOJUN HUANG, YUQIU GU, ZHONGQING ZHAO and QIQHUA ZHU Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box, 919-986-6, Mianyang, Sichuan Province, China, 621900

The experimental study on ka photon emission from different thickness Cu foils (3 pm, 10 pm, 30 pm) irradiated by a 795 nm, 30 femtosecond laser pulse at the relativistic regime (up to 5x10" W/cm2) was performed on

SILEX-I laser facility at Laser Fusion Research Center, China. The strong dependence of ka yields on target thickness, laser intensity, and angle of incidence of laser were presented. An optimized laser intensity (for which the laser k conversion efficiency was maximized) at -lxlO19 Wpm2/cm2 for 3 pm and 10 pm targets was determined. Both the ponderomotive heating and resonant absorption contributed to the laser absorption and enhancement of the production of ka photons at relativistic regime. From the comparison of the measured ka yields and Monte Carlo calculations, we found the recirculation of hot electrons due to the sheath in the target rear surface played an important role when the foil thickness is less than the half of the laser pulse length. Because of the nanosecond prepulse, the scale length in the target front side is much larger than the scale length on the target rear side for the three micron foils, therefore the static sheath field on the foil rear surface was much stronger than the static sheath field on the foil front surface. Most hot electrons propagated to the target rear surface reflected back into the foil and finally escaped from the target front surface. This means the travelling distance of the hot electrons for the three micron foils was in fact six microns. This recirculation of hot electrons led to the ka yields of three micron Cu foil were equivalent to the ka yields of six micron Cu foils. On the other hands, due to the strong inhibition of electric field near the foil front surface, the stopping range of hot electrons was about 10 microns in the Cu foil. Much weaker sheath fields presented in the target rear surface for 10&30 micron foils. The recirculation of the hot electrons for these relatively thick foils just played minor roles in the k production.

71 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary

Abstracts - posters c Abstracts - posters )

pi. Resonance at cross section increased fusion gain in volume ignition of clean H-"B reaction M. Kouhi1. M. Ghoranneviss', B. Malekynia2, H. Hora3, N. Azizi4 'Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran-Poonak, Iran 2Department of physics, Islamic Azad University, Gachsaran Branch, Gachsaran, Iran 'Department of theoretical physics, University of New South Wales, Sydney/Australia 4Islamic Azad University, Khoy Branch, Khoy, Iran

The nuclear fusion cross section of hydrogen (proton) with the boron isotope 11 (p-"B) is interesting for re- examining the computations for laser driven fusion. It is well known that reheating of fusion plasma due to re-absorption of alpha particles and partial Bremsstrahlung radiation enhanced fusion gain. The gain of fusion energy has been calculated for H-"B fusion reaction in inertially confined plasma of high density with volume ignition model. Results are reported for the laser driven fusion energy by spherical compression where the resonance maximum was not included before. We report on new computations of the volume ignition of high density spherical compression of p-"B fusion gains showing a considerable increase due to the resonance especially at energies which are interesting for possible laser fusion.

P2. Interferometry of laser pulse wavefront at the output of subpicosecond facility "SOKOL-P" D. S. Gavrilov. A.G.Kakshin, E.A.Loboda Russian Federal Nuclear Center - All-Russian Research Institute of Technical Physics (RFNC- VNIITF), 456770, Snezhinsk, p.o. box 245, Russia. E-mail: [email protected]

We report about experiments on study of wavefront of laser beam 130 mm in aperture by a radial-shear interferometer. Following wavefronts were put to the test: the wavefront of chirped pulse of 500 ps in duration at the output of amplifying channel (at the input of laser pulse compressor), and the wavefront of 0.7...0.8 ps pulse at the output of the compressor, after propagation through air and a window of the vacuum chamber to the parabolic mirror. Energies of these pulses at a nominal pumping mode of the amplifying channel were correspondingly 12...15 J and 10...12 J. Comparative measurements of the static aberrations of wavefront, and dynamic aberrations arising at a pumping of the amplifying channel, at a nominal and small pulse energy at the input of the channel have been performed. Last mode has been realized for elimination of non-linear phase deformations of the wavefront for the purpose of separated studying of thermooptical aberrations. Wavefront defocus at the input of the compressor leads to magnification of pulse duration at targets and deterioration of focusing of radiation, and achievement of the maximum radiant intensity becomes impossible. Taking into account the measured aberrations of the wavefront at the input and output of the compressor compensation of dynamic defocus of the wavefront has been performed, the defocus and astigmatism of the wavefront at the output of the compressor thereby have been eliminated and pulse duration 0.7 ... 0.8 ps in focus of the parabolic mirror is obtained. Moreover, the account of aberrations has allowed to raise accuracy of positioning of a target, the minimal a focal spot diameter of 5... 6 microns FWHM with the content of energy 20...30 % within this diameter has been thus obtained. Small diameter of a focal spot is provided thanks to rather high temporary contrast of a laser pulse amounting 10" on intensity. Thus, as a result of application of the featured method the intensity of laser radiation on a target I ~ (1.. .2) -10" Wcm2 is reached.

74 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 74 c Abstracts - posters

P3. Stimulated Brillouin scattering phase-locking using a transient acoustic standing wave excited through an optical interference field Ondrej Slezak1. Hong Jin Kong2, and Milan Kalal1 "Czech Technical University in Prague, Brehova 7, 115 19 Prague 1-, Czech Republic 2>Korea Advanced Institute of Science and Technology, Daejeon, Korea 305-701

Analytical description of an experimentally verified scheme[l] leading to a phase-locked stimulated Brillouin scattering (SBS), used in a laser beam combination systems[2], is presented. The essential condition for the phase-locking effect for SBS is the fixation of the starting position and time of the acoustic Brillouin wave. It is shown that the starting position fixation of this acoustic wave may have its origin in a transient acoustic standing wave initiated by an arising optical interference field produced by the back-seeding concave mirror. This interference field leads to a stationary density modulation of the medium. However, the way to the formation of this density modulation leads via the acoustic standing wave. An appropriate solution, in the form of the standing wave, was obtained from solving the acoustic wave-equation using the electrostriction as a driving force. As a consequence of the damping term included in this equation the acoustic standing wave becomes gradually attenuated and, contrary to the undamped solution published earlier, thus constitutes a truly transient phenomenon. Using a mathematical formalism similar to that which is used for the SBS description in the case of a random phase, the coupled equations describing the phase-locked SBS were derived. Contrary to the case without the back-seeding mirror, where the wave chosen from the thermal noise background subsequently plays the role of a trigger of the stimulated process, in this case it is replaced by the transient standing wave produced as a consequence of the presence of an optical interference field arisen in the focal region of the back- seeding concave mirror. References [4] H.J. Kong, S.K. Lee, J.W. Yoon, J.S. Shin and S. Park, Advances in Lasers and Electro Optics. 978-953- 307-088-9,229 (2010). [5] H.J. Kong, J.S. Shin, J.W. Yoon, and D.H. Beak, Nucl. Fusion 49, 125002 (2009).

P4. Dual-beam operation of the Astra Gemini laser facility Brvn Parry. Nicola Booth, Oleg Chekhlov, John Collier, Edwin Divall, Klaus Ertel, Peta Foster, Steve Hawkes, Chris Hooker, Victoria Marshall, David Neely, Rajeev Pattathil, Daniel Symes, Yunxin Tang and Brian Wyborn Central Laser Facility, STFC Rutherford Appleton Lab, Harwell Science & Innovation Campus, Oxfordshire, OX11 0QX, UK

Gemini is a Petawatt class Ti:Sapphire laser system at the Rutherford Appleton Laboratory, UK. It was designed as a dual beam laser, with two independently configurable 800 nm beams delivering 15 J to target in 30 fs pulse duration, giving 0.5 PW peak power per beam. It is capable of reaching intensities over 1022 W/cm2. Gemini can achieve a maximum repetition rate of one shot every 20 seconds, allowing it to deliver hundreds of shots per day; a feature which makes it unique among PW lasers. Already this has proved valuable in experiments involving electron acceleration in gas jets. The first Gemini beamline became operational in 2008. Commissioning of the second beam was deferred to allow earlier access to the facility by experimental scientists, and to develop operational experience. In this mode, Gemini has already produced significant results from a number of advanced plasma physics experiments. The second beam of Gemini is now coming online, with the first dual beam experiment starting in June 2010. The flexibility offered by two short pulse, ultra high intensity beams is another aspect that makes this laser system unique. The dual beams enable versatile configurations and illumination geometries, facilitating a wider range of experiments than is possible with only a single beam. Operationally however, it introduces additional

75 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) 3 factors which must be monitored and controlled in order to achieve experimental success. The beams must be timed with respect to each other with accuracy less than the pulse duration. The beam foci must also be overlapped spatially, and the stability of both these factors maintained over extended periods. We report on the second beam commissioning process, including the latest results on the characteristics, stability and spatio-temporal overlap of the two beams. We present details of amplifier performance, along with measurements of beam quality, focal spot, pulse duration and contrast, to give a detailed picture of Astra Gemini in its full operating mode.

P5. Simulation of absorption of femtosecond laser pulses in solid-density copper N.G. Karlykhanov, P.A. Loboda, N.A. Smirnov, A.A. Shadrin Russian Federal Nuclear Center - All-Russian Institute of Technical Physics (RFNC-VNIITF), 13, Vasilyeva St., Snezhinsk, Chelyabinsk region, 456770, Russia

We present the simulations of absorption of femtosecond laser pulses in copper using modified ID Lagrangian ERA hydrocode [1] enabling to model short-laser-pulse absorption, heat conduction, and plasma dynamics. Numerical modeling involved thermodynamic functions calculated by using first-principles Full-Potential Lin- earized Maffin-Tin Orbitals method (FP-LMTO) [2] and chemical model of dense plasma utilizing supercon- figuration approach [3]. The results of simulations are compared to experimental and other theoretical data. Acknowledments The work has been supported in part by the International Science and Technology Center under the project # 3755. References [1] N.M. Barysheva et al. Comput. Math. Math. Phys. 22, 156 (1982); A.I. Zuev et al. Comput. Math. Math. Phys. 32, 70 (1992). [2] S.Yu. Savrasov, D.Yu. Savrasov. Phys. Rev. B. 46, 12181 (1992). [3] P.A. Loboda, V.V. Popova, A.A. Shadrin. Contrib. Plasma Phys., 49, 738 (2009).

P6. Ionization-induced excitation of residual current density in a plasma produced by a few-cycle laser pulse A.A. Silaev and N.V. Vvedenskii Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod 603950, Russia, phone: +7(831)4164993, fax: +7(831)4160616, e-mails: [email protected], [email protected]

The present work is focused on analytical and numerical investigation of the phenomenon of excitation of low- frequency residual currents in plasmas produced by few-cycle laser pulses. At present, this phenomenon is of great interest due to the possibility of using it to convert efficiently laser pulses into low-frequency radiation, in particular, into radiation of the terahertz frequency band [1-4]. The residual current density (RCD) is the initial push leading to the polarization of the laser-produced plasma and excitation of emitting oscillations in this plasma. In the general case, the frequencies of these oscillations are determined by the pressure of the ionized gas and the density of the generated plasma. For a wide range of gas pressure and laser pulse parameters, the frequencies of the waves emitted by the plasma lie in the terahertz band [2, 5]. We find the efficiency of RCD excitation as a function of the carrier-envelope phase (CEP), duration, and intensity of few-cycle laser pulses. Our numerical calculations are based on the developed semiclassical approach and ab initio quantum-mechanical approach, which is based on solving the three-dimensional time- dependent Schrodinger equation. We focus mainly on relatively low values of the laser-pulse intensity

76 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

( ~ 1014 -1016 Wcm 2 ) and determine the domain of applicability of the semiclassical approach to the case of such pulses. We develop an analytical model for the description of the considered phenomenon and derive closed-form analytic formulae which can be used to find the dependences of RCD on the laser pulse parameters. We determine optimal parameters of the laser pulse corresponding to the highest efficiency of RCD excitation. The results obtained show that the considered phenomenon may be used for the generation of high-power terahertz radiation as well as to monitor the CEP of few-cycle laser pulses. It is shown that the phenomenon of RCD excitation can be studied on the basis of the same theoretical models and realized efficiently under the same experimental conditions as ionization-induced generation of high harmonics and attosecond pulses [6]. Acknowledgements This work was supported by the Russian Foundation for Basic Research, the Presidential Council on Grants of the Russian Federation, the Ministry of Education and Science of the Russian Federation, and the Dynasty Foundation. References [1] Krefi M„ Loffler T„ Thomson M.D. et al., Nature Phys., 2006, v. 2, p. 327. [2] Gildenburg V.B., Vvedenskii N.V., Phys. Rev. Lett., 2007, v. 98, p. 245002. [3] Silaev A.A., Vvedenskii N.V., Phys. Rev. Lett., 2009, v. 102, p. 115005. [4] Silaev A.A., Vvedenskii N.V., Phys. Scr., 2009, v. T135, p. 014024. [5] Kostin V.A., Vvedenskii N.V., Opt. Lett., 2010, v. 35, p. 247. [6] Krausz F„ Ivanov M„ Rev. Mod. Phys., 2009, v. 81, p.163.

P7. New reduced-dimensionality models for efficient quantum-mechanical description of ultrafast strong-field phenomena A. A. Silaev. M. Yu. Ryabikin, and N. V. Vvedenskii Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov Street, Nizhny Novgorod 603950, Russia, phone: +7(831)4164993, fax: +7(831)4160616, e-mails: [email protected], [email protected], [email protected]

The development of theoretical approaches to the description of strong-field phenomena caused by ultrashort laser pulses is topical for studying the interaction of atoms and molecules with intense laser fields. In this work, we address two phenomena which attract much attention and can be observed under similar experimental conditions, namely, when a gas is ionized by ultrashort laser pulse. The first phenomenon is the excitation of high-order harmonics of the driving field frequency in the electron current, which leads to the generation of vacuum ultraviolet and soft X-ray radiation, as well as the attosecond pulse production [1]. The second phenomenon is the excitation of a quasi-dc residual current in the laser-produced plasma, which results in the generation of radiation having a frequency below the laser one, e.g., terahertz waves [2, 3]. We present new one-dimensional (ID) and two-dimensional (2D) quantum-mechanical models for the description of such phenomena for the case a hydrogen (H) atom, and the generalization of these models to the case of various noble-gas atoms. The shape of the electrostatic potential produced by an atomic ion is shown to influence significantly the rates of the processes in the dynamics of atomic electron, and even more, the rates of the tunneling and above-barrier ionization, which is of utmost importance for the considered phenomena. The results of solving the time-dependent Schrodinger equation with the ID and 2D potentials, which we propose, are compared with the results of the ab initio three-dimensional calculations for the H atom. We find the regions of laser pulse parameters, where the results obtained with proposed models have much better accuracy than the results provided by the models used earlier.

77 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) Acknowledgements This work was supported by the Russian Foundation for Basic Research, the Presidential Council on Grants of the Russian Federation, the Ministry of Education and Science of the Russian Federation, and the Dynasty Foundation. References [1] Krausz F„ Ivanov M„ Rev. Mod. Phys., 2009, v. 81, p.163. [2] Gildenburg V.B., Vvedenskii N.V., Phys. Rev. Lett., 2007, v. 98, p. 245002. [3] Silaev A.A., Vvedenskii N.V., Phys. Rev. Lett., 2009, v. 102, p. 115005.

P8. Photo-dissociation of methane in the strong femtosecond laser field E. Irani, Z.Dehghani, R.Sadighi-Bonabi Department of Physics, Sharif University of Technology, 11365-9161, Tehran, Iran [email protected]

Dissociation of methane in intense laser beam at the intensity of 8xl013wcm2,800nm wavelength and lOOfs pulse width is investigated. By using the quantum manners to field dissociation mechanism and numerical

study of time dependent Schrodinger equation for selective bond of CH4 molecule with split operator method, the results of our calculation have a good agreement with reported experimental data. This approach for first time successfully enables us to achieve dissociation probability by finding the dynamics of propagation of quantum wave packet and moving on the dressed potential energy surfaces. The results also improved more than 20 % by modifying laser pulse shape in two- rectangular pulse shape, where in this situation delayed photo dissociation is occurred and the yield is increased more than twenty percent. Because of the advantage of broad band frequency width of femtosecond lasers, a superposition of many associated states is created and the constructive enhancement or the destructive cancellation of various excitation routes can be exploited to maximize the dissociation probability and yield of a desired product.

P9. The effect of the two tailored femtosecond laser pulses in the enhancement of methane dissociation R. Sadighi-Bonabi, Z. Dehghani and E. Irani Department of Physics, Sharif University of Technology, 11365-9161, Tehran Iran Corresponding email: [email protected]

Based on the gradient optimization method a useful approach for dissociation of the methane molecule is introduced. This analytical model produces an optimized two tailored rectangular laser pulses which dissociates + the molecular ion CH4 with maximum probability of 1. In this approach the field assisted dissociation is used by a semi-classical view. It is assumed that only the selective dissociative bond is in direction of the laser electric field are effective. Saturation is found for dissociation of the mentioned molecular bond, where the first pulse should have higher intensity than the second pulse. In addition to that, the sensitivity of the dissociation probability to the initial bond length and the control of the desired product channel by variation of the laser intensity and its duration of laser field is presented.

78 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

PIO. Generating phase-matched high-order harmonics using CEP controlled few-cycle pulses K. Kovacs1. V. To?a', P. Dombi2, M. A. Porras3 'Natl. Inst. R&D Isotopic and Molecular Technologies, 65-103 Donath str., 400293-Cluj-Napoca, Romania 2Research Institute for Solid-State Physics and Optics, Konkoly-Thege M. lit 29-33, H-l 121, Budapest, Hungary 3Universidad Politecnica de Madrid, Rios Rosas 21, ES-28003Madrid, Spain

Recently Porras and Dombi showed [1], by performing analytical calculations, that it is possible to freeze or to control the variation of the carrier-to-envelope phase (CEP) of propagated few-cycle laser pulses in the focal region. These methods consist in changing the variation of the beam's spot size for different spectral components at the focusing element and/or placing a dispersive slab (or medium) in the way of the propagating pulse.

We developed a numerical method to calculate the electric field of the laser in these special configurations, which allowed us to simulate high-order harmonic generation (HHG) and perform phase-matching (PM) calculations for different types of CEP variations of the input pulse. The fundamental pulse at 800 nm wavelength has a FWHM of 5 fs and peak intensity not exceeding 0.4 PW/cm2. HHG is assumed to take place in neon at low pressure (< 40 Torr) and the interaction medium is placed close to the focal region of the pulse. Under these conditions ionization rate remains low during HHG, thus in the PM calculations we do not take into account the dispersion due to plasma contribution and neutrals. We assume that the electric field is not perturbed during propagation and we perform PM calculations for different harmonic orders in the whole interaction region.

We will present the effect of different CEP variations of the fundamental pulse on the high-harmonic spectra and will explore the possibilities to obtain strong coherent HH radiation under favorable PM conditions.

References [1] M. A. Porras and P. Dombi, Optics Express 17, 19424 (2009)

Pll. Dissipative light-bullets in the filamentation of femtosecond pulses Miguel A. Porras'. Isabel Gonzalo2 'Departamento de Ftsica Aplicada, Universidad Politecnica de Madrid,. Rios Rosas 21, 28003 Madrid, Spain 2Departamento de Optica, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain

With the growing interest in filamentation in solid and liquid media, the regime of filamentation with anomalous dispersion is receiving more attention [1, 2]. In this work we show that basics aspects of the filament dynamics in this regime can be explained in terms of a novel type of light-bullet, which is not of solitary or of conical types, but a wave-packet that maximizes the energy dissipation into the medium while remaining localized and stationary in propagation.

We first show that a nonlinear optical medium at a given carrier wave length at which dispersion is anomalous, supports "dissipative" light-bullets, i.e., waves localized in space and time and that propagate without change as a result of a balance between nonlinear compression and nonlinear absorption. Among them, the particular dissipative light-bullet with the highest possible dissipation is unique in a given medium, in the sense that all its properties are fixed by the properties of the medium at the carrier wave length. In this light-bullet, self-focusing continuously transports energy towards the pulse center by an amount that just compensates for the nonlinear losses. Figure 1(a) shows the radial profiles of the dissipative light-bullets that maximizes energy dissipation for several orders of multi-photon absorption responsible for the nonlinear losses.

79 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

We have also found that this dissipative light-bullet tends to be spontaneously formed in the filamentary dynamics in media with anomalous dispersion. Figure 1(b) shows the peak intensity, the total energy and losses of a pulse that undergoes self-focusing and filamentation in an ideal medium with only Kerr nonlinearity and multi-photon absorption. This simple model reproduces the particularly long filament "segments" and the "burst" observed in experiments and in more accurate simulations. [1,2] The peak intensity in the filament is identical to that of the dissipative light-bullet with maximum dissipation, and the initial Gaussian radial profile is seen to transform gradually [Fig. 1(c)] into that of the dissipative light-bullet of maximum dissipation.

normalized radius

Fig. 1 (a) Spatiotemporai radial profiles of the most dissipative light-bullets in media with K-phototi absorption, (b) Peak intensity (solid curve), energy (dashed curve) and losses (dotted curve) upon self-focusing of a Gaussian pulse of width 0.011 cm (duration 44.5 fs) at 1550 nm and with 50 times the critical power for self-focusing infused silica, modelled as a medium with only Kerr nonlinearity and nonlinear losses (K=10). (c) Radial intensity profiles of the pulse (solid) approaching the radial profile of the most dissipative light-bullet (dotted) upon self-focusing.

Dissipative light-bullets then provide an alternative explanation to filament dynamics in media with anomalous dispersion and relevant nonlinear losses, which does not involve the problematic concepts of multidimensional solitons or of conical waves. References [ 1 ] D. Moll and A. L. Gaeta, Opt. Lett. 29, 995-997 (2004). [2] L. Berge and S. Skupin, Phys. Rev. E 71, 065601 (2005).

P12. Effects of external magnetic field on harmonics generated in laser interaction with underdense plasma M. Faghihi-Nik1. M. Ghorbanalilu', B. Shokri2 'Physics Department, Azarbaijan University Of Tarbiat Moallem, Tabriz, Iran 2Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran

Generation of harmonic radiation is an important subject of laser plasma interaction and attracts great attention due to a wide range of applications [1]. It has been seen that intense electromagnetic and quasi-static transverse magnetic fields are generated in laser plasma interaction [2]. An extremely intense magnetic field (up to hundreds of MG) has been observed by experimental measurements in interaction of short laser pulses with plasma [3], These self-generated or applied magnetic fields affect the propagation of the laser pulses [4]. In most laser interactions with homogeneous plasma, odd harmonics of laser frequency are generated [5], In this paper, we point out the possibility of even harmonics generation when a linearly polarized laser beam propagates in homogeneous plasma in the presence of a transverse magnetic field. It is shown that applying external field induces a transverse current density oscillating twice of the laser field which leds to generation of second harmonic radiation. This current density is derived using the perturbation method, and the steady state amplitude of the second harmonic obtained by solution of the wave equation. By the same procedure the current density and then the steady state amplitude of higher order harmonics are calculated. The efficiency of

80 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) harmonic generation (the ratio of harmonic power to incident power) is a drastically function of the strength of external magnetic field. It is found that the efficiency of even harmonics is zero in the absence of magnetic field and increases as the magnetic field is increased. For odd harmonics, applying the external magnetic field enhances the generated harmonics as well. The conversion efficiency also increases with increase in plasma density and intensity of the laser beam. References [1] P. Gibbon, IEEE J. Quantum Electron. 33, 1915 (1997). [2] J. Fuchs et al, Phys. Rev. Lett. 80, 1658 (1998). [3] U. Wanger et al, Phys. Rev. E 70, 026401 (2004). [4] M. Ghorbanalilu, Phys. Plasmas 17, 023111 (2010). [5] W. B. Mori et al, IEEE Trans. Plasma Sci. 21,110 (1993).

P13. Independent control of arbitrary orders of dispersion at the high power end of CPA lasers M. GorbeH A. Borzsonyi1, P. Jojart13 , M. Kovacs3, K. Osvay3 'CE Optics Kft., Kigyd u. 4, H-6720 Szeged, Hungary 2Faculty of Mechanical Engineering and Automation, Kecskemet College, 6001 Kecskemet, Pf 91. Hungary department of Optics and Quantum Electronics, University of Szeged P.O. Box 406, H-6701 Szeged, Hungary

One of the most crucial issues in chirped pulse amplification (CPA) systems is the precise temporal recompres- sion of the pulses hitting the target. In case of few cycle high intensity lasers, the stabilization of the carrier- envelope phase (CEP) of the pulses is also required. An acousto-optical programmable dispersion filter can satisfy both aims, providing dispersion (pre)compensation up to the fourth order of dispersion and make the CEP shift stable [1,2]. Its use is, however, limited to a pulse intensity of 100 MW/cm2, hence its application is restricted to the front end of the (OP)CPA laser systems. A simple optical arrangement consisting of wedges with different materials and different apex angles was proposed recently for isochronic control of CEP of a pulse train [3]. In this paper we show that assembly of wedges can be specifically designed to tune only one of the dispersion coefficients, while all the others, including CEP, remain practically unchanged. Wedge pairs changing solely the zeroth (CEP) and second order (group delay) dispersion (GDD) are experimentally presented along with a triplet of wedges tuning the third order dispersion (TOD) only. The experiment was carried out with the use of spectrally resolved interferometry (SRI). A Michelson- interferometer was illuminated by 100 nm bandwidth laser pulses of a Ti:Sapphire oscillator. The sample arm of the interferometer contained the wedge assembly, set to near Brewster-angle incidence at each surfaces, designed for tuning the required order of dispersion. At the output of the interferometer the spectral interference between the pulses from the sample and reference arms was resolved with a spectrograph. The dispersion was tuned by perpendicular shift of the entire wedge assembly to the laser beam. In the measurements spectral interferograms were recorded and evaluated at each spatial position of the assembly. Three different wedge combinations, two doublets and a triplet were designed and examined carefully. The first doublet consisted of an N-PK51 and a Lithosil-QlE193 wedge and was designed to CEP tuning, the second one from N-SSK2 and N-LaK7 aimed to change the GDD only. The measured tuning slopes were 1.66 rad/mm and 3.6 fs2/mm, respectively. The triplet compiled of N-LaK7, N-LaSF46 and NSF57 wedges was made for TOD tuning: 130 fs3/ mm was measured. All wedge assemblies only changed the selected spectral phase derivative while keeping the others practically zero. The residual angular dis-persion was also measured [4], and found to be well below the detection limit of 0.2 prad/nm. We have proved that a combination of optical wedges is capable to control the required order of dispersion, including CEP, independently to all the other orders. Since the loss is negligible and the (bulk) damage threshold is high, we believe that such specially designed wedge combinations can significantly contribute to the fine tuning of dispersion and CEP just prior to the compressor of high power laser systems like Petawatt Field Syntheser (PFS), Extreme Light Infrastructure (ELI), but also of smaller scale laboratory few cycle systems.

81 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

References [1] Osvayet al., ICUIL 2010 [2] Koke et al., CLEO 2010, paper CTuA2 [3] Gorbe et al, Opt. Lett. 33, 2704 (2008) [4] Varju et al, Appl.Phys.B 74, S259 (2002)

P14. Plasma effects in attosecond pulse generation from ultra-relativistic laser-plasma interactions T. J. M. Boyd1, R. Ondarza-Rovira2 1 Centre for Theoretical Physics, University of Essex, Colchester C04 3SQ, UK 2Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Mexico 11801, D.F., Mexico

Particle-in-cell simulations were performed to examine the influence of plasma effects on high harmonic spectra from the interaction of ultra-intense p-polarized laser pulses with overdense plasma targets. Furthermore, a theoretical model is proposed to explain the radiation mechanism that leads to attosecond pulse generation in the reflected field. It is shown that plasma harmonic emission affects the spectral characteristics, causing deviations in the harmonic power decay as compared with the so-called universal 8/3-decay. These deviations may occur, in a varying degree, as a consequence of the extent to which the plasma line and its harmonics affect the emission. It is also found a strong correlation of the emitted attosecond pulses with electron density structures within the plasma, responsible to generate intense localised electrostatic fields. A theoretical model based on the excitation of Langmuir waves by the re-entrant Brunei electron beams in the plasma and their electromagnetic interaction with the laser field is proposed to explain the flatter power spectral emission -described by a weaker 5/3 index and observed in numerical simulations- than that of the universal decay.

P15. Development of the RTP crystal applications for Q-switching operation & Second Harmonics Generation R. Sh. Alnayli Physics Department, Al-Qadissiyah University Dewaniyha-IRAQ P.O Box-88 Email: [email protected]

A dialed theoretical studies on performances of the ideal RTP crystal for the electro optical application as Q-switching laser operation and for nonlinear optics application as second harmonics generation are accomplished in this paper. Single or pair RTP crystal of excellent quality with dimensions 5x5x7.5 mm3 have proposed as element model to combined Q-switching operation and frequency doublers for 1.06 pm wave length laser. In order to get and interpolate the optimum conditions to combined both of these operations by application this RTP model, The main aim of this work was investigated the most influent parameters on the performance of the electro optical Q-switching laser operation such as, the voltage requirement, contrast and extinction ratios, the birefringence effective and withstand threshold . on the other hand the influences of the ray walk off, thermal effective on the efficiency of the second harmonics generation as well are investigated. The results were satisfied for the goals of this paper.

82 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters

P16. Temporal Talbot effect in propagation of attosecond electron waves Sandor Varro Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences H-1525 Budapest, POBox 49, Hungary, E-mail: [email protected]

The rapid development in extreme strong-field and extreme short-pulse laser physics provide us with many potentials to explore the dynamics of fundamental processes taking place in light-matter interactions and in propagation of electromagnetic [1] or matter waves [2]. The present paper discusses the propagation of above- threshold electron waves generated by (not necessary ultra-short) strong laser fields. Recently we have shown [3] that - in analogy with the formation of attosecond light pulses by interference of high-order harmonics - the wave components of photoelectrons are naturally assembled in attosecond spikes, through the Fourier synthesis of these de Broglie waves. We would like to emphasize that the proposed scheme does not presupposes an a priori ultrashort excitation. Owing to the inherent dispersion of electron waves even in vacuum, the clean attosecond structure (emanating perpendicularly from a metal target surface) is gradually spoiled due to destructive interference. Fortunately the collapsed fine structure recovers itself at certain distances from the source within well-defined 'revival layers'. This is a temporal analogon of the optical Talbot effect representing the self-imaging of a grating, which is illuminated by stationary plane waves, in the near field. The 'collaps bands' and the 'revival layers' introduced in ref. [3] have been found merely on the basis of some numerical illustrations of the dynamics of the above-threshold current. The locations and durations of the attosecond layers turned out to show certain reguralities. In the meantime we have derived approximate analytic formulae for the propagation characteristics, with the help of which we can keep track of the locations of the 'collaps bands' and the 'revival layers' on a larger scale. We shall report on these semiclassical results, and also discuss their possible connection with the recently found entropy remnants [4] in multiphoton Compton scattering by electronic wave packets. Acknowledgement This work has been supported by the Hungarian National Scientific Research Foundation OTKA, Grant No. K73728. References [1] Mourou G A, Tajima T and Bulanov S V, Relativistics optics. 2006 Rev. Mod, Phys. 78, 309-371 [2] Krausz F and Ivanov M, Attosecond physics. 2009 Rev. Mod. Phys. 81,163-234. [3] Varro S and Farkas Gy, Attosecond electron pulses from interference of above-threshold de Broglie waves. Laser and Particle Beams 26, 9-19 (2008). See also arXiv:0705.0212 [physics.plasm-ph] [4] Varro S, Entangled states and entropy remnants of a photon-electron system. Physica Scripta, in press. See also arXiv: 0910.4764 [quant-ph]

P17. Optimization of the produced wakefield by two intense short laser pulses S.Zare, R.Sadighi-Bonabi Department of Physics, Sharif University of Technology, 11365-9161, Tehran Iran [email protected]

In this work it is shown that the electrons can be trapped and accelerated to the higher energies by two pulses in comparing to the single laser pulse with the same energy. A detailed analytical study of wakefield amplification making use of two laser pulses copropagating one behind the other, with a fixed time between them is presented. Three basic pulses in the shape of rectangular, Gaussian and sinusoidal are considered. It is found that when the first of the two laser pulses is rectangular and the second pulse is sinusoidal the produced wake field is maximum.

83 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P18. Attosecond pulse manipulation with chirped multilayer mirrors Z. Diveki1. Ch. Bourassin-Bouchet2, D. Guenot1, T. Ruchon1, S. de Rossi2, F. Delmotte2, E. Meltchakov2, B. Carre1 and P. Salieres1 ' CEA-Saclay, IRAMIS, Service des Photons, Atomes et Molecules, 91191 Gif-sur- Yvette, France 2 Laboratoire Charles Fabry, Institut d'Optique, Univ Paris sud, CNRS, RD128 Campus Polytechnique, 91127 Palaiseau, France

Attosecond light pulses (1 as = 19"18 s) can nowadays be produced by high-harmonic generation (HHG) in the Extreme Ultraviolet (EUV) [1], In this spectral range, optical systems are much more difficult to design than in the visible range, partly because of the absorption of materials. Several techniques were proposed to overcome the problem of attosecond pulse control after the high harmonic source, for example by using filters [2], plasmas or gas mediums [3], Multilayer aperiodic chirped mirrors, which efficiently reflect EUV radiation, were recently proposed in order to manipulate [4] such pulses. But the possibility of phase control over large spectral bandwidth has not yet been demonstrated.

We designed and manufactured three plane multilayer mirrors with optimized reflectivity and controlled spectral phase in the 35-55 eV range near 45° incidence. Their reflectivity was characterized on the Elettra Synchrotron and their spectral phase, on an attosecond pulse source at CEA SPAM, providing a full characterization of their spectral response. We report on the characterization of these mirrors and show how they affect the temporal profile of the attosecond pulses. Such pulses provided by the HHG process are intrinsically chirped. We demonstrate that they can be recompressed using our designed multilayer aperiodic mirrors.

Until now attosecond pulse manipulation was restricted to some shaping functions mainly determined by the material of the used optical elements. In this presentation we also propose a more flexible way to shape the pulses giving relatively high intensities. A combination of two mirrors may provide us with an active attosecond pulse-shaper. It allows the realization of some simple functions as a tunable pulse compression, or the shaping of a single, double or multiple sub-100 as pulses, the properties of which can be set by simply turning the pulse- shaper. Acknowledgments This work was supported by the ANR project 07-BLAN-0150. The multilayer fabrication have been carried out on CEMOX (Centrale d'Elaboration et de Metrologie des Optiques X References [1] P.M. Paul et al. Science, 292, 1689 (2001) [2] R. Lopez-Martens et al. Physical Review Letters, 94, 033001, (2005) [3] D.H. Ko et al. New Journal of Physics, 12, 063008 (2010) [4] A.-S. Morlens et al. Optics Letters, 31, 3095, 2006

P19.

Molecular orbital imaging using attosecond pulses generated in N2 S. Haessler1, Z. Diveki1. J. Caillat23, W. Boutu1, C. Giovanetti-Teixeira23, T. Ruchon1, T. Auguste1, P. Breger1, A. Maquet23, B. Carre1, R. Taieb23, P. Salieres1 1 CEA-Saclay, IRAMIS, Service des Photons, Atomes et Molecules, 91191 Gif-sur-Yvette, France. 2 UPMC Univ. Paris 06, UMR 7614, Laboratoire de Chimie Physique-Matiere et Rayonnement, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France. 3 CNRS, UMR 7614, LCPMR F-75005 Paris, France.

The strong interaction of a molecule with a laser field frees by tunnel ionization an attosecond electron wave packet that probes its bound state half a laser cycle later as it re-collides with the core. Rich information on

84 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) the (possibly transient) electronic [1,2] and nuclear [3] configuration is encoded in the attosecond XUV burst emitted during recombination, a process called high-order harmonic generation (HHG). Complete characterization (intensity, phase and polarization) of this observable gives access to the transition dipole moment over a large momentum span. This transition dipole may allow direct imaging of the radiating molecular orbital using a tomographic procedure [1]. For the first time we succeeded to characterize the intensity, phase and polarization of the XUV emission in aligned N2 molecules. Our measurements evidence multi-orbital contributions to the attosecond emission [4] and also reveal the ellipticity of the harmonics. Recent experimental and theoretical studies have revealed that molecules could be tunnel ionized from several orbitals simultaneously [5]. These different orbitals lead to interfering contributions in the attosecond emission. We were able to separate these contributions and by using the tomographic molecular orbital reconstruction technique, HOMO and HOMO-1 orbitals were reconstructed in N . These reconstructions show remarkable agreement with theoretical simulations and also provide us with the sign changes in the orbital wave functions. An investigation was addressed to the validity of the plane wave approximation in our calculation. The coherent superposition of the HOMO and HOMO-1 orbitals provides time-resolved experimental images of the wave packet ('hole') left empty after coherent tunnel ionization from both orbitals [7]. The recombining electron wave packet probes the 'hole' at the instant of recombination providing information about the electronic structure of the molecule at that moment. This imaging of a dynamical wavepacket serves as a test of feasibility for intra-molecular imaging with Angstrom spatial resolution and attosecond temporal resolution. References [1] J. Itatani et al., Nature 432, 867-871 (2004). [2] W. Boutu et al., Nature Physics 4, 545 (2008). [3] S. Baker et al., Science 312, 424 (2006). [4] S. Haessler et al., Nature Physics, 6, 200 (2010). [5] O. Smirnova et al., Nature 460, 972 (2009).

P20. Measurements for the radiation spectra of fast Z-pinches produced at compression of multi-wire arrays on the "Angara-5-1" facility E. A. Bolkhovitinov1, M. V. Fedulov2, E. V. Grabovsky2, A. N. Gritsuk2, G. M. Oleinik2, A. A. Rupasov1. A. S. Shikanov1, G. S.Volkov2, V. I. Zaitsev2 'P. N. Lebedev Physical Institute, 53 Leninsky Prospect, Moscow 119991, Russia 2Troitsk Institute for Innovative and Thermonuclear Research, Troitsk, Moscow region, 142190, Russia

The measurements results on the radiation spectra of fast z-pinches produced at compression of cylindrical multi-wire tungsten and aluminum arrays in the experiments on a high-current "Angara-5-1" facility are presented. Cylindrical multi-wire arrays had linear mass 200-400 |xg/cm and the initial diameter 12-20 mm. The pinch current was about 3 MA with pulse duration of 140 ns and peak power 3 TW. The radiation spectra are measured within the range of 50-900 eV quanta by a spectrometer with transmission diffraction grating, where the radiation is recorded on the UF-4 X-ray film. An electromagnetic curtain shutter was used to protect the transmission grating from fast microparticles produced by the erosion of high-voltage electrodes. The radiation spectrum of 1-3 keV quanta was recorded by a convex crystal wide-range spectrometer. Total yield of the radiation was measured by a thermocouple calorimeter. The main part of the tungsten plasma radiative energy proves to correspond to the quasi-continuous spectrum within the range of 80-300 eV quanta. Measurements of the tungsten plasma radiation spectrum with spatial resolution by a pinch radius have shown that the effective transversal size (diameter) of the pinch is not higher than 1 mm. In the case of aluminum plasma an intensive linear radiation of the [H] - and [He] -like ions have been recorded along with a continuous and linear radiation of the [Li]- and [Be]-like ions with the range of 100-300 eV

85 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) quanta. Spectral measurements of the aluminum plasma radiation with spatial resolution by the pinch radius have shown that the effective transversal size (diameter) of the pinch is around the value of 1.5 mm. Within the framework of the stationary collisional-radiative model, in respect of the [H]- and [He]-like ion spectral lines relative intensities, the parameters of the aluminum plasma pinch, namely, the electron temperature T -550 eV 20 3 and electron density ne~3x 10 cm" have been determined. Acknowledgements The work was supported by the Russian Foundation for Basic Research under the projects 08-02-01394 and 08-02-00317.

P21. Spectral phase shift and residual angular dispersion of an acousto-optic programmable dispersive filter A. BorzsonviH M. Merd3, A. P. Kovacs1, M. P. Kalashnikov4, K. Osvay1 ' Department of Optics and Quantum Electronics, University of Szeged P.O. Box 406, H-6701 Szeged, Hungary 2 CE Optics Kft., Kigyd u. 4, H-6720 Szeged, Hungary 3 Research Group on Laser Physics, Hungarian Academy of Sciences, Dom ter 9, Szeged, Hungary 4 Max Born Institute, Max-Born-Strafie 2/A, D-12489 Berlin, Germany

There is an increasing demand for active and precise dispersion control of ultrashort laser pulses. In chirped pulse amplification (CPA) laser systems, the dispersion of the optical elements of the laser has to be compensated at least to the fourth order to obtain high temporal contrast compressed pulses. Nowadays the most convenient device for active and programmable control of spectral phase and amplitude of broadband laser pulses is the acousto-optic programmable dispersive filter (AOPDF) [1], claimed to be able to adjust the spectral phase up to the fourth order. Although it has been widely used, surprisingly enough there has been only a single, low resolution measurement [2] reported on the accuracy of the induced spectral phase shift of the device. In our paper we report on the first systematic experiment aiming at the precise characterization of an AOPDF device. In the experiment the spectral phase shift of the AOPDF device was measured by spectrally and spatially resolved interferometry, which is especially powerful tool to determine small dispersion values with high accuracy [3], Besides the spectral phase dispersion, we measured both the propagation direction angular dispersion (PDAD) [4] and the phase front angular dispersion (PhFAD) [5]. Although the two quantities are equal for plane waves, there may be noticeable difference for Gaussian pulses. PDAD was determined simply by focusing the beam on the slit of an imaging spectrograph, while PhFAD was measured by the use of an inverted Mach- Zehnder interferometer [5] and an imaging spectrograph. In the measurements, the spectral phase shift and both types of angular dispersion have been recorded upon the systematic change of all the accessible functions of the acousto-optic programmable dispersive filter. The measured values of group delay dispersion (GDD) and third order dispersion (TOD) have been found to agree with the preset values within the error of the measurement (lfs2 and 10fs3, respectively). In case of continuous mode operation of the AOPDF, the angular deviation and angular dispersion was found to vary more than 0.15 mrad and 1 mrad/pm when the GDD was changed from Ofs2 to +104 fs2. This effect is attributed to thermally induced refractive index gradient in the acousto-optical crystal caused by the dissipated acoustic power. In low repetition rate triggered mode, however, this phenomenon was experimentally negligible. In all cases the angular dispersion had actually a non-zero offset value of 0.5 prad/nm, but this is practically negligible in almost every case of use. References [1] F. Verluise, et al., Opt. Lett. 25 575 (2000). [2] T. Oksenhendler, et al., CLEO 1176 (2003). [3] A. Borzsonyi et al., Opt. Comm. 281, 3051-3061 (2008) [4] K. Osvay et al., IEEE J.Sel.Top.Quant.Electr. 10, 213-218 (2004) [5] K. Varju et al., Appl.Phys.B 74, S259-S263 (2002).

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P22. Modification of K-line emission profiles in laser-created solid-density plasmas A. Sengebusch. H. Reinholz and G. Ropke University of Rostock, Institute of Physics, Rostock (Germany)

X-ray emissions in the keV energy range have shown to be suitable radiation to investigate the properties of laser-created solid-density plasmas [1, 2], We use the modifications of inner shell transitions due to the environment to characterize these plasmas. A theoretical treatment of spectral line profiles based on a self-consistent ion sphere model is applied on moderately ionized mid-Z materials, such as titanium, silicon and chlorine. We observe large contributions of satellite transitions due to M-shell ionization and excitation. To determine the composition a mixture of various excited and ionized ionic states embedded in a plasma has to be considered. Plasma polarization effects that cause shifts of the emission and ionization energies are taken into account. K-line profiles are calculated for bulk temperatures up to 100 eV and free electron densities up to 1024 cm 3 in order to analyze recent measurements with respect to the plasma parameters of electron heated target regions. Moreover, in high-intensity laser-matter interactions, inevitable prepulses are likely to create preplasma and shocks within the target before the main pulse arrives. We investigate the influence of density gradients due to prepulses on the spectral profiles. Further, radial bulk temperature distributions as well the composition of the created warm dense matter are inferred [3, 4]. References [1] U. Zastrau, P. Aubert, V. Bernshtam, et al., Phys. Rev. E 81 026406 (2010). [2] E. Stambulchik, V. Bernshtam, L. Weingarten, et al., J. Phys. A: Math. Theor. 42 214056 (2009). [3] A. Sengebusch, H. Reinholz, G. Ropke, U. Zastrau, et al., J. Phys. A: Math. Theor. 42 214061 (2009). [4] A. Sengebusch, H. Reinholz, G. Ropke, Contrib. Plasma Phys. 49 748 (2009).

P23. NATALIE, a multidetector diagnostic to characterize laser produced particle beams: applications. C. Plaisir1, M. Tarisien1, F. Gobet1, F. Hannachi1, M.M. Aleonard1 1 Universite Bordeauxl, CNRS-IN2P3,Centre d'Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, 33175 Gradignan, France.

Ultra High Intensity lasers produce energetic particles such as electrons, protons, photons within a large domain of energies. In a range between a few MeV to few tens of MeV, these beams may open new opportunities to study nuclear isomer production in plasma [1] in relation with astrophysical problems. Such studies require the knowledge of the particle energy and angular distributions to quantify possible future experiments. For this purpose, we have developed a standalone integrated data acquisition system to characterize proton and electron beams (converted into photons via bremsstrahlung) using nuclear activation techniques. This system called NATALIE (Nuclear Activation Technique for Analysis of Laser Induced Energetic particles) is composed of sixteen Nal detector pairs used to count the activity of various samples activated via (y,xn) or (p,n) reactions for example. The setup is based on a coincident technique which allows (V activity measurements with very low background and leads to accurate nuclear activation yields determination. Geant4 simulations are used at different steps of the data analysis to deduce the energy and angular distributions of the laser-induced particle beams from the experimental data. Two applications are presented as illustrations regarding the characterization of electron and proton beams. Acknowledgments: We acknowledge the support of IN2P3/Region Aquitaine for a BDI grant (C.P.) and financial supports from ANR (contract n° ANR-07-JCJC-0158), Conseil Regional dAquitaine (contract n° 200713040005) and IN2P3/CNRS.

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References: [1] F. Hannachi et al., Plasma Phys. Control Fusion 49, B79-B86 (2007). [2] M. Tarisien et al., submitted to RSI [3] M. Gerbaux et al., RSI 79, 023504 (2008).

P24. Investigation of copper X-ray spectra on SOKOL-P laser facility at intensities of 1017-1019 W/cm2 D. A. Vikhlvaev, D. S. Gavrilov, A. G. Kakshin, E. A. Loboda, V. A. Lykov, V. Y. Politov, A.V. Potapov, V. N. Saprykin, K.V. Safronov, P. A. Tolstoukhov Russian Federal Nuclear Center - All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Russia

Energy of the laser pulse interacting with solid and gas targets partially transmits to fast electrons, which in turn slowing-down in target, create a continuous and characteristic radiation. Investigation of this radiation is important for studying the processes of generation and transport of fast electrons in target material. On 20 TW picoseconds laser facility SOKOL-P, the research of copper targets continuous X-ray spectrum was conducted in the range of photon energies of0.6-3000 keV and yield of Cu-Ka characteristic line was measured. A spectrograph with flat crystal (LiF d = 2.15 A) was used to measure the Ka-radiation of copper. Registration of the spectrum was carried out on a CCD camera. Front-side measurements were performed for targets of 35 and 50 pm thickness. Yield of Cu-Ka practically does not depend on the intensity of laser radiation in the range of three orders. Measurements from the back side were conducted for targets of 35 pm thickness. They show a monotonic increase of the line yield depending on the intensity with saturation at about 1018 W/cm2. Measurement of laser plasma continuous spectrum in the energy range 0.6-4.5 keV was carried out using X-ray spectrometer based on spherical mirrors of total external reflection. In combination with X-ray mirrors, the filters that allow registration the radiation in five narrow energy regions were used. The spectral distribution of soft X-rays in the energy range 0.6-4.5 keV is characterized by the effective electron temperature of ~ 0.5 keV. The hard X-rays spectra measurement in the energy range 25-90 keV was carried out at the front of a target by K-filter method using spectrometer with semiconductor detectors DDR 18/0.5. The X-rays with energies above 100 keV were detected using gray lead filters method by three-channel spectrometer based on photoelectronic multiplier FEU-60 with CsJ (Tl) scintillators. Spectral distribution of X-rays (e> 100 keV) is characterized by effective temperature of electrons in the hundreds of keV diapason, changing the value of Teff from 200 keV at I = 3-10'7 W/cm2 to 600 keV at I ~ 10" W/cm2. In 20-100 keV range of quanta energy the X-ray spectra have a nonmonotonic character with maximum value at about 5-101' keV / keV at energy of 50-60 keV.

88 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P25. Time-of-flight technique for detection of fast ions accelerated by high power lasers D. Margarone'. J. Krasa1, A. Picciotto2, A. Velyhan1, J. Prokupek1, L. Laska1, L. Rye3, P. Parys3, L. Torrisi4, P. Musumeci5 and B. Rus1 'Institute of Physics, ASCR, v.v.i. & PALS Centre, Prague, Czech Republic 2Fondazione Bruno Kessler - IRST, Trento, Italy institute of Plasma Physics and Laser Microfusion, Warsaw, Poland 4Physics Department of Messina University, Messina & INFN - Laboratori Nazionali del Sud, Catania, Italy 5Physics and Astronomy Department of Catania University, Catania, Italy

Time-of-flight (TOF) technique is a possible approach for laser-plasma ion beam diagnostics since many years. In fact it provides time-resolved measurements which are fundamental for a detailed study and understanding of basic ion beam parameters, such as kinetic energy, ion species and charge states, current, total charge, shot- to-shot reproducibility, etc. Multi-MeV beams of light ions have been produced using the 300 ps, kj-class iodine laser, operating at PALS facility in Prague. Real-time ion diagnostics was performed by the use of various TOF detectors: standard ion collectors (IC) with and without absorber thin films, new prototypes of single-crystal diamond and SiC detectors, and an electrostatic ion spectrometer. In order to cut off a long photopeak contribution and avoid the overlap with the signal from ultrafast particles, e.g. protons, the ICs have been shielded with different Al foils. Otherwise, the use of large-band-gap semiconductor detectors (> 3 eV) also ensured cutting of the long plasma photopeak and additionally high sensitivity to the very fast proton/ion beams. Finally, complementary measurements realized by the use of an ion-energy-analyzer (IEA) spectrometer have been carried out in order to recognize different ion species and charge states in the expanding laser-plasma. Processing of the obtained experimental TOF data, including estimation of the plasma fast proton maximum and peak energy, ion peak current density, total number of fast protons, as well as deconvolution processes and ion transmission calculations for different metallic filters used, is shown. Maximum attainable proton energy and current has been optimized varying the target composition, laser energy and focal spot diameter. Experimental results are presented, discussed and compared with literature data.

References [1] D.Margarone, J.Krasa, L.Laska, A.Velyhan, T.Mocek, J.Prokupek, E.Krousky, M.Pfeifer, S.Gammino, L.Torrisi, J.Ullshmied and B.Rus, Rev. Sci. Instr. 81, 02A506 (2010). [2] J. Krasa, A. Velyhan, D. Margarone, E. Krousky, J. Ullschmied, ]. Skala, L. Laska, K. Jungwirth and K. Rohlena, "Generation of high currents of carbon ions with the use of a sub-nanosecond NIR laser pulses", Rev. Sci. Instr. 81, 02A504 (2010).

P26. Advanced X-ray and XUV optics for plasma spectroscopy E. Forster. I. Uschmann, O. Wehrhan, U. Zastrau, et al. Institute for Optics and Quantum Electronics, Friedrich Schiller University Max Wien Platz 1, 07743 Jena, Germany

In the last decade, much effort has been given in development of modern dedicated XUV and x-ray free electron lasers with unique properties. Femtosecond laser plasma sources provide ultra-short x-ray pulses of high peak brilliance and can thus be complementary x-ray sources to the undulator based sources. All these modern x-ray sources need dedicated x-ray optics for diagnostics and applications, respectively. The availability of femtosecond XUV pulses from free-electron lasers such as FLASH in Hamburg (Germany) opens up new possibilities to study dense plasmas. These states of matter are characterized either by XUV

89 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters self-emission of XUV Thomson Scattering. In any case, high resolution XUV spectrometers are highly desired. Additionally, these diagnostics have to be flexible, comparatively small and highly efficient in order to serve various dedicated experiments. X-ray spectroscopy is one of the most important diagnostics of plasmas in the context of laser fusion. Depending on the aims of these experiments (i) monochromatic x-ray images or (ii) high resolution spectra combined with either spatial or time resolution can be obtained. Sophisticated monochromatic imagers with up to 10 toroidally bent crystals have been developed to study the implosion processes in laser fusion experiments; time- resolved maps of plasma parameters were evaluated from the data. High-power femtosecond lasers provide a practical, relatively inexpensive, powerful x-ray flash source. Information on production efficiency, the energy distribution and transport of hot electrons is needed to maximize x-ray output in desired K-shell emission lines or continuum ranges so that peak brilliances comparable to those of synchrotrons may be feasible. Combining these new sources with bent crystal optics enables diffraction experiments on sub-picosecond time scales. Laser-pump x-ray-probe experiments have shown evidence of structure changes in several crystals within 250 fs. These x-ray optics have been designed in our institute using raytracing and Bragg reflection codes for the ID or 2D bent crystals or combinations thereof. In the preparation process, extreme care has been taken over crystal perfection, selection of optimum reflections, precision bending, measurement of imaging and reflection properties. X-ray topographic cameras and diffractometers are used to check the relevant properties of the analyzer crystals.

P27. Spectral identification of tissue's malignant changes I.Gruia1, S.Yermolenko2, M.I.Gruia3, C.Gavrila" 'University of Bucharest, Faculty of Physics, Romania 2Chernivtsi University, Ukraine 3Institute of Oncology Bucharest, Romania 4Technical University of Civil Engineering Bucharest, Romania

Early detection of malignant transformation is a goal of modern medicine and to this end there is an impressive number of approaches from the scientific field that tries to identify early changes preceding malignant transformation in order to establish a correct diagnosis. This work aims is to combine the optical and biochemical techniques for identifying the changes in membrane dynamics of growth and development of experimental solid tumours. During the purpose has been used experimental Walker 256 carcinoma graft in Wistar rats, followed from day 7 up to day 24 from inoculation of tumour cells. Optical techniques were used fractalometry laser polarization in the preclinical diagnosis of pathological changes and degenerative- dystrophy of experimental tissue, and in terms of biochemical tumour tissue was determined the reaction of lipid peroxidation monitored by the malondialdehyde (MDA), the end product assays of reaction. In addition were followed also the total antioxidants as a response of the endogenous defences systems. The results indicate a rising profile of the processes investigated by the 14th day after tumour graft, following a decrease due to lack of substrate enzymatic reactions, specifically the double links of polyunsaturated fatty acids in the membranes change during tumour development. These data are consistent with the changes of the optical investigated parameters. It is shown that in all the cases the linear dichroism appears in bio tissues with the cancer disease the magnitude of which depends on the tumour growth of the cancer process development. The phenomenon of the linear dichroism formation has a selective character: maximum values A are observed in the area A=410^430 nm and in the area A=500-h530 nm, for the wavelength \<300 nm and X>750 nm A is almost zero or zero. The linear dichroism magnitude depends on the thickness of samples that's why at thicknesses d=10-^12pm when the transmission is 80% and more, it doesn't become apparent at the measurements on the spherical photometer, in this case it is better to conduct the transmission investigation in the direct beam. As the linear

90 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) dichroism is lacking for healthy tissues, then the obtained results can have diagnostic values with the purpose of detection and estimation of the stage of the cancer disease development.

P28. Analysis of the complex interferometry diagnostics applicability to deuterium clusters spatial density distribution measurements Michaela Martinkova1. Milan Kalal1, and Yong Joo Rhee2 ' Dept. of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in Prague, Trojanova 13, 120 00 Prague 2, Czech Republic 2 Lab. for Quantum Optics, Korea Atomic Energy Research Institute P.O. Box 105 Yusong, Daejeon 305-600, Korea

In recent years interactions of high-intensity femtosecond lasers with deuterium clusters leading to Coulomb explosions and subsequent production of fusion neutrons attracted considerable attention [1] due to their importance for inertial confinement fusion research and relevant material studies. Already created theoretical models (e.g., [2]) still do not explain all features of laser-clusters interactions. From experiments performed [3] it became clear that in order to maximize the neutron yield, finding a dependence of clusters size and especially their spatial distribution on experimental conditions becomes crucial. Identifying a suitable diagnostics to measure the deuterium clusters spatial distributions experimentally thus became an important task. In recent years, in order to repeat the fusion neutron production from Coulomb explosions of deuterium clusters, successful series of experiments were performed in the Laboratory of Quantum Optics in KAERI using the Ti:Saphire laser system (30 fs, I > 1016 W/cm2) [4]. In our contribution results of a feasibility study of deuterium clusters spatial density distribution measurements performed by complex interferometry [5] will be presented. It will be demonstrated that this particular diagnostics features an excellent suppression of detrimental effects introduced by diagnostic beam lower quality as well as by imperfections of optical components (including misalignment of the interferometer). For the purpose of this feasibility study close-to-reality computer generated interferograms were created based on relevant experimental data obtained in KAERI using their Ti:Saphire laser (30 fs, I > 1016 W/cm2) and cryogenic system. These simulated interferograms included an effect of a small density perturbations caused by generated clusters in their presumed most likely regions of appearance. Comparison of the reconstructed phase- shifts with the undisturbed ones was made and found suitable from the point of sensitivity of this diagnostics to detect a presence of the clusters in the gas/clusters mixture. It should be emphasized that unless the phase-shift differences as such would be detectable, proceeding to reconstruction of clusters densities has no real meaning. Acknowledgement This research has been supported by the IAEA RC No.: 13781; by the CTU in Prague grant No.: CTU0916314; by the Grant Agency of the Czech Republic grant No.: 202/08/H057; by the Ministry of Education, Youth, and Sports of the Czech Republic Research Project LC528, by the grant KONTAKT No. ME933. This work has been also supported in part by the EU FP7 joint R&D project "Collaboration on HiPER project" funded by Korean MEST through NRF. References [4] T. Ditmire, J. Zweiback, V.P. Yanovsky, T.E. Cowan, J.H. Hartley, G. Hays, and K.B. Wharton, Nature 398, 489 (1999). [5] A.R. Holkundar and N.K. Gupta, Phys. Plasmas 15,123104 (2008). [6] J. Zweiback, T.E. Cowan, J.H. Hartley, R. Howell, K.B. Wharton, J.K. Crane, R.A. Smith, and T. Ditmire, Phys. Plasmas 9, 3108 (2002). [7] S. Nam, J. Han, Y.J. Rhee, Y.H. Cha, D.H. Kwon, Y.W. Lee, J.H. Mun, S. Lee, S. Kwon, and H. Cha, J. Korean Phys. Soc. 52,1020 (2008). [8] M. Kalal, O. Slezak, M. Martinkova, and Y.J. Rhee, J. Korean Phys. Soc. 56, 287 (2010).

91 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P29. Pulse laser ablated thin film of BN and related diagnostics Radhaballabh Bhar", Manoranjan Khan and A. K. Pal Department of Instrumentation Science, Jadavpur University, Kolkata 700 032, India [email protected]

Boron Nitride (BN) is an excellent material for its various good properties. In the last few years, there was an extensive worldwide effort to synthesize boron nitride (BN) in thin films form. BN thin films have mechanical, structural, electrical and optical properties comparable to those of bulk materials. BN system is analogous to the carbon system in many respects. Boron nitride is mostly available in the form of cubic boron nitride(c- BN) and hexagonal boron nitride(h-BN). Thin film of c-BN is one of the most promising materials as it pos- sess properties comparable to that of diamond in terms of thermal conductivity, chemical inertness, electrical resistivity, optical band gap and mechanical hardness and also has diverse potential applications in electronics, optics and hard coating. Pulsed Laser Ablation is one of the increasingly important techniques for deposition of materials in thin film form. Pulsed lasers of nanosecond duration still represent the most widely applied system. Laser generated plasma plume produced during the process of Laser Ablation play a crucial role in the quality of the film. Information regarding formation and evolution of the laser induced plasma plume from the target and on the transport of the ablated species to the substrate is of critical importance in understanding the dynamics involved in pulsed laser deposition of thin film. So, particular attention is necessary for investigating roles of plasma parameters during the process of deposition of film. We are setting up a Pulse Laser Deposition(PLD) laboratory at Jadavpur University, India. Laser ablation experiment will be performed by using a Nd:YAG laser(\ =1064 nm & its 2"d /3rd harmonics, Make-Expla, Model -NL303 HT) with pulse duration 4-6 ns repetition rate 10 Hz. The stainless steel ablation chamber be 6 evacuated by a turbomolecular pump. The base pressure of the chamber 6 X 10 torr. After evacuation pure N2 gas be introduced from the bottom of the chamber. The gas pressure of the chamber be controlled from 0 to 10 torr by changing the evacuation rate using a variable conductance valve. A sintered BN target will be fixed on the rotating holder in the vacuum chamber. Nd:YAG laser pulse at wavelengths 1064 nm and its harmonics be used to irradiate the BN target at 45° from the normal direction. The deposition substrate can be heated upto 800°C. Plasma generated during deposition will be diagnosed by using optical emission spectroscopy, Ion/ Langmuir probe measurement etc. Smooth and chemically etched Si and glass will be taken as substrate with

TiN or Sn02 etc. as interface to match adherence for depositing c-BN. Deposited film will be characterized by SEM,AFM,XRD and FTIR to understand growth processes so that we can optimize the film with higher quality. Deposited film will also be studied critically in respect of plasma and laser parameters. Species coming out due to laser ablation will be studied by observing spectroscopic data. References: [1] 'Pulsed Laser Deposition of Thin Films(Wiley, New York), 1994 Eds.,D.B. Chrisey, and Hubler G.K. [2] 'Laser Ablation Synthesis and Characterization of Nitride Coatings', 1997, J. of Mat. Engg. And performance, 6(5), 577-82. [3] 'Pulsed Laser Vaporization and Deposition',2000, P.R. Willmott and J.R.Hurber, Review of Modern Physics, &2(1), 315-28. [4] 'Temporal and Spatial Variations in Electron Density and Blackbody Temperature in the Initial Phase of Laser Ablation BN plasma 2008, Koichi Sasaki, Shin Yasuda and Noriharu Takada., Plasma and Fusion Research, 3(023), 1-5.

92 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters 3

P30. Electron bunch distance measurement based on driver/witness type plasma wakefield acceleration T. Konigstein1. B. Hidding1, S. Karsch2, O. Willi1, G. Pretzler1 'Heinrich-Heine Universitat, Diisseldorf 2Max-Planck-Institutfiir Quantenoptik, Garching

Electron double (or multi-) bunches are important in Laser Wakefield Acceleration (LWFA) as well as in Plasma Wakefield Acceleration (PWFA). Simulations can show that they are often generated by trapping and acceleration in consecutive wave buckets in case of LWFA, and their production is highly desirable for driver/witness type PWFA. While measuring spiked energy spectra can be an indication of the presence of electron multi-bunches, this does not reveal anything on the time structure of the multi-bunches. Various methods have been developed in order to measure electron bunch durations and distances, for example via electro-optical sampling or coherent optical transition radiation [1,2, 3], but these setups are complex and are limited to tens of fs at best. Based on 2D PIC-simulations, we analyze the potential of using the energy gain/loss in a driver/witness PWFA scenario as an alternative/additional novel method to determine electron bunch distances and profiles which might allow resolution down to the fs-scale. Here, the first electron bunch sets up a plasma wave in a test plasma, which can lead to energy transfer to the second bunch via the electric wakefields [4, 5, 6]. By sampling the density of the test plasma and analyzing the energy spectra after the interaction with a fixed test plasma length, detailed information on the electron bunch distance as well as the driver profile can be obtained with high accuracy. The theoretical as well as experimental requirements, implications and limitations of the scheme are discussed. Acknowledgements This work was supported by DFG SFB TR-18. References [1] J. van Tilborg et al., Phys. Rev. Lett. 96, 014801 (2006) [2] Y. Glinec et al., PRL 98, 194801 (2006) [3] A. Debus et al., PRL 104, 084802 (2010) [4] P. Chen et al., PRL 54, 693-696 (1985) [5] P. Muggli et al., C.R. Physique (2009) [6] B. Hidding et al, PRL 104, 195002 (2010)

P31. X-ray emission characteristics of foam target plasmas A.A. Fronva. N.G. Borisenko, M.L. Chernodub, Yu.A. Merkuliev, M.V. Osipov, V.N. Puzyrev, A.T. Sahakyan, A.N. Starodub, B.L. Vasin, O.F. Yakushev P.N. Lebedev Physical Institute ofRAS, Moscow, Russia

Experimental results of laser radiation interaction with a foam targets are presented. The spatial, temporal and energy characteristics of x-ray plasma radiation have been investigated. The pinhole-camera and Schwarzschild objective have been used for the plasma image formation in different spectral ranges. The plasma image is registered by the Schwarzschild objective in a narrow spectral range 180 - 200 A. Spectral characteristics of x-ray radiation registered by pinhole-camera have been defined by means outer filters. The use of the filters with different transmission curves allowed one to determine the localization of x-ray radiation with fixed wavelength. Spatial resolution accounts 16 (im in the pinhole-camera diagnostic channel and 2.5 pm in the Schwarzschild objective diagnostic channel. The plasma images in the intrinsic x-ray radiation show that the emission area in the transverse direction with respect to the direction of the propagating heating radiation exceeds the focal spot size. This fact indicates that the target heating in the transverse direction is due to internal energy of the created plasma. The average value of plasma electron temperature is ~ 0.4-1.4 keV.

93 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

Acknowledgements The work is partly supported by the Russian Foundation for Basic Researches, grant # 10-02-00113 and by Federal Target Program "Research and scientific-pedagogical cadres of Innovative Russia" (grant 2009-1.1- 122-052-025).

P32. Laser action on rare earth doped nitride semiconductor thin layers A.Oussif, and M. Diaf Laboratoire de physique des lasers et de spectroscopie optique (LAPLASO) University ofAnnaba, PB12 Sidi Amar 23000 Annaba Algeria E-mail: [email protected]

The structure, chemical composition, properties, and their relationships in solids lay the foundation of materials science. Recently, great interest in rare-earth (RE)-doped wide-bandgap semiconductors, which combine the electronic properties of semiconductors with the unique luminescence features of RE ions, is from the fundamental standpoint of structure-composition-properties of solids. At first, a significant amount of work has been reported on the study of infrared emissions from Er3+ doped semiconductors because Er3+ exhibits luminescence at 1.54 pm, a wavelength used in optical communications. Since Steckl and Birkhahn first reported visible emission associated with Er from GaN:Er films, the RE-doped semiconductors have received considerable interest for possible application in lightemitting devices. Molecular-beam epitaxy (MBE) and metalorganic chemical vapour deposition (MOCVD) have been used mainly to grow GaN host films. The RE dopants were typically incorporated into the host films by in situ doping during the growth or by ion implantation after the growth. GaN doped with rare-earth elements (RE) hold significant potential for applications in optical devices, since they show sharp intense luminescence which is only minimally affected by temperature variations. Among the various RE dopants, Eu seems to be the most interesting, since it yields red luminescence 622 nm which has not been realized in commercially available light emitting devices (LEDs) that use InGaN active layers. We have earlier reported single crystalline growth of Eu-doped GaN and nearly temperature independent red luminescence at 622 nm originating from the intra-4/-4/transition of the Eu3+ ion. The red luminescence was analyzed and determined to be generated through trap-level-mediated energy transfer from the semiconductor host.

P33. The variation of effective temperature of stochastically heated electrons in laser pulse A.S. Orekhov, N.G. Borisenko, Yu.V. Krylenko, Yu.A. Mikhailov, G.V. Sklizkov. Lebedev Physical Institute, 119991, Russia, Moscow, Leninskyy pr„ 53.

The ultra-energy electron generation in laser plasma is very important in the field of thermonuclear fusion and other applications. The model of stochastic acceleration of relativistic electrons in a specific wave packet of electromagnetic field has been proposed by the authors earlier. The space-temporal structure of Nd-laser focused beam with stochastic phase disturbance of each spectral component had been then considered as a source of random forces [1]. The dynamics of relativistic electron distribution function is simulated by numerical computation. Electrons are heated by multimode laser radiation. The perturbation of electromagnetic field local phase, which is caused by small scale random density variation in a low-density structured target, is taken into account as a source of a force acting randomly at electron motion, similar to stochastic phase perturbation in peculiar wave packet. It is shown that the electron energy increase is a few orders of magnitude more than oscillatory motion energy in a plain wave when electron trajectory stochastic perturbations occur. On the basis of 2D numerical simulation

94 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) the behaviour of relativistic electron distribution function during bell-shaped laser pulse of duration equal to 2*104 wavelengths has been analysed. The analytical formulas of distribution function have been derived for relativistic electrons as an ideal gas. The distribution functions calculated for different laser radiation intensities in the range of 1014-1017 W/cm2 are compared with analytical expressions for corresponding equilibrium distributions. For the reason of this collation the temperature characteristic for the ensemble of stochastically heated electrons has been defined. The temporal dependence of electron temperature has been obtained. It is shown, that essential electron temperature growth happens during the initial 300-100 wave periods depending on laser flux density. In the middle of the pulse it is observed approximately linear growth of electron temperature, which comes to saturation at the pulse tail. The directivity of electrons, escaping interaction area depends slightly on the incoming laser radiation intensity in the concerned range. On the contrary it depends essentially on the presence of backside reflected wave. For example, this emission is nearly isotropic in the case of standing wave, that is correlated with corresponding phase diagrams. Acknowledgments This work was supported by Russian Foundation for Basic Research under Project. No. 08-02-00913-a. HiPER program is acknowledged. References 1. Y.A. Mikhailov, L.A. Nikitina, G.V. Sklizkov, A.N. Starodub, and M.A. Zhurovich, Laser and Particle Beams 26, 525-536 (2008).

P34. Protons energy loss for laser fusion driven ion acceleration B. Malekynia Department of Physics, Islamic Azad University, Gachsaran Branch, Gachsaran, Iran b_malekynia@iaug. ac. ir

The anomalous generation of plasma blocks by interaction of petawatt-picosecond laser pulses permits side-on ignition of uncompressed solid fusion fuel following an improved application of the hydrodynamic Chu-model for deuterium-tritium. The new possibility of side-on laser ignition depends on accelerated ions and produced ions beams of high energy particles by the nonlinear ponderomotive force of the laser pulse in the plasma block, a re-evolution of the early hydrodynamic analysis for ignition of inertial fusion by including inhibition factor, collective effect of stopping power of alpha particles and the energy loss rate reabsorb to plasma by the protons of plasma block being reduced by about a factor 40. Acknowledgments This work supported by plasma physic research center of LAU at Theran, Iran by the IAEA (Vienna) coordinated research program No. 13508. The author thanks Professor Heinrich Hora for supervisor of Ph. D Theses. References [1] B. Malekynia, H. Hora, N. Azizi, M. Kouhi, M. Ghornneviss, G. H. Miley and X. T. He, Laser and Particle Beams Journal, 28, 3(2010) [2] J. Badziack, Opto-Electronic Review, 15,1(2007). [3] L. Spitzer, Physics of Ionized Gases, Interscience publishers, Inc. , New York (1950). [4] H.C. Kranzer, Phys. Fluids 4, 214(1961). [5] S. T. Butler and M. J. Buckingham, Physical Review, 126,1(1962)

95 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P35. Miniaturized fiber in-line interferometer fabricated by femtosecond laser micromachining D. N. Wang and Ying Wang Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Horn, Kowloon, Hong Kong, P.R. China

An in-line fiber MZI is attractive due to its simplicity and compactness. Various types of in-line fiber MZI structures have been developed, based on interference between the fundamental core mode and the higher order cladding mode, with size of typically in the order of millimeters or centimeters, and have very small effective refractive index (RI) difference between the core mode and the cladding mode (<0.01). This work presents a new structure of in-line fiber MZI for RI measurement with high sensitivity and precise sensing location. A MZI cavity is formed by removing part of the fiber core near the core and cladding interface, which results in splitting of the input beam into two portions, IjnJ and lin2. While / remains traveling along the fiber core, / has to propagate through the micro-cavity, and the interference happens when the two output beams recombine at the fiber core.

Fig. 1 In-line fiber MZI fabricated by use of femtosecond laser irradiation, (a) Schematic of the structure (top view). D represents the removed size of fiber core; L is the cavity length; I and / ^ m=l, 2, are the input and output optical intensities propagated in the fiber core and micro-cavity, respectively, (b) Optical microscopic image of the micro-cavity (side view), (c) SEM image of the micro-cavity, the dashed white circle indicates the fiber core (cross-section view)

The essential difference between our MZI and those reported previously lies in the fact that our device is based on the interference of the guided mode in the core and the unguided mode travelling through the micro-cavity. The RI difference between the two arms of the MZI is very large (> 0.10), which allows a dramatic reduction of the cavity length while maintaining a high RI sensitivity. Moreover, the position of the RI change can be precisely located due to the small size of the micro-cavity. The interferometer created in this work exhibits a high RI sensitivity, —9370 nm/RIU (refractive index unit) within the RI range between 1.31 and 1.335. Moreover, a precise sensing location can be ensured owing to the small size of the interferometer. Such a fiber device has high potential in chemical and biological sensor applications. Acknowledgement This work was supported by Hong Kong SAR government through a GRF (general research fund) grant PolyU 5306/08E and The Hong Kong Polytechnic University Research Grant A-SA52.

96 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 96 c Abstracts - posters )

P36. R&D of an experimental technique for condensed media femtosecond laser ablation recoil momentum evaluation in sub-pN-s range E. Yu. Loktionov'. A.V. Ovchinnikov2, Yu.Yu. Protasov1, D.S. Sitnikov2 'Bauman Moscow State Technical University, Russia, 105005, Moscow, 2nd Baumanskaya str. 5 2Joint Institute for High Temperatures of RAS, Russia, 125142, Moscow, Izhorskaya str. 13/2 [email protected]

Radiation absorption depth substantially decreases under femtosecond laser pulses action on condensed media (as compared to longer laser pulses), allowing an efficient action on condensed materials "transparent" at a given wavelength under ordinary conditions and removal of thinner layers of substances during laser ablation. Fine dosing of the mass flow down to Am~10_11-10 12 g under femtosecond laser irradiation makes it possible, 2 3 n 12 at average expansion velocities of erosive vapors ofv_~10 -10 m/s, to impart a recoil momentum JM~ 10 -10" N-s to the ablating target. Obtaining of such a small value of the minimum controlled momentum transferred as a result of a single-shot laser action is a necessary condition, which cannot be achieved using nanosecond or longer laser pulses. The problem of recoil momentum measuring methods sensitivity increase is especially difficult to be solved when low radiation energy pulses are used. Sensitivity of ballistic pendulums and strain gauges for measuring 6 5 the recoil momentum is approximately AJM~10~ -10~ N-s, and for torsion pendulums (torsion balances), -9 8 AIM~ 10 -10" N-s. When a polymer target is irradiated with femtosecond laser pulses with energies usually less 4 than E~ 10~ J, maximum recoil momentum value does not exceed IM~10" N-s, and the measurement technique resolution must be at least AJ ~10~9 N-s. M An experimental technique for recoil momentum measurement with an accuracy of A/ <10"n N-s during femtosecond laser ablation of condensed media has been developed. The technique is based on combined microinterferometry of an ablating target surface (Michelson-Linnick scheme) and near-surface photoerosion gas-plasma flows (Mach-Zehnder scheme). The results of momentum coupling coefficient and laser radiation to gas-plasma flow kinetic energy conversion efficiency experimental evaluation under action of ultrashort

(tfwhm~45-70 fs) UV-NIR (A-266, 400, 800 nm) laser pulses on condensed media (metals Cu, Zr, Ti, Mo, Nb 2 and polymers (C2F4)n, (CH20)n) both in ambient and vacuum (p~10 Pa) conditions are presented.

P37. Experimental investigation of condensed media ultrashort laser ablation multifactor processes E. Yu. Loktionov1, A.V. Ovchinnikov2, Yu.Yu. Protasov1, D.S. Sitnikov2 'Bauman Moscow State Technical University, Russia, 105005, Moscow, 2nd Baumanskaya str. 5 2Joint Institute for High Temperatures of RAS, Russia, 125142, Moscow, Izhorskaya str. 13/2 [email protected]

Femtosecond laser ablation of polymers finds wide application in science and engineering, since it allows fine dosing of the material amount removed from the irradiated surface at a minimum thermal influence region. Due to the high density of the radiation power, the absorption mechanism changes opening additional possibilities of laser processing of transparent materials. Adequate technological application of laser ablation requires information on processes occurring both on the irradiated surface and in the gas-plasma flow of removed material.

Processes on the surface and in the near-surface region of polymeric ((CH20)n, (C2F4)n) and metallic (Cu, Zr, Ti,

Mo, Nb) targets irradiated with femtosecond (tfiwjm~45-70 fs) UV-NIR (A-266, 400, 800 nm) laser pulses were studied using an interferometric system consisting of Michelson and the Mach-Zehnder interferometers. Two- plane observation of the near-surface plasma formation (SPF) resulting from intense laser exposure made it possible to study the crater formation dynamics in most detail, since optical characteristics of the SPF introducing distortions to the pattern recorded in the interference microscope arm were determined. Irradiation was

97 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters performed both under atmospheric conditions and in vacuum (p~ 10~2 Pa) with energy densities of 0.1 -40 J/cm2 at a focal spot radius ro~20 ^m. The mass flow dynamics from the exposed surface (the total mass flow depends on the pulse energy, reaching at the optimum, i.e., when exceeding the spectral-energy ablation threshold by a factor of e, m* -10~4 g/J), the spatiotemporal distribution of the electron density in the SPF (reaching 10" cm-3 for the first tens of nanoseconds after exposure), the mass-averaged velocity of particle expansion (-1-7 km/s in vacuum, where the particle expansion velocity and its variance appreciably exceed these values under atmospheric conditions), and shock-wave front propagation velocities (-2-7 km/s), pressures (-1-8 MPa) and temperatures (~ 1-5 eV) were studied at various exposure parameters.

P38. Analytical study of the thermal lensing and effects in end pumped solid state Nd:YAG laser with a super Gaussian profile Firoozeh Karimi Moghadam1, Meysam Hamzehlooei2 1 Malayer Branch-Islamic Azad University,P.O.Box65718/l 17 2Air Industries Research Institute

High power solid state lasers have been investigated extensively because of their numerous applications. It is essential to generate a beam with high quality and high accuracy in such lasers. One of the most important aspects of design of lasers is amount of the heat loaded on an active material crystal. When a solid state iaser is pumped, a lot of heat is generated as a result of non uniform temperature distribution; this by itself results in a variety of thermal effects like creation of stresses, variation of end surfaces, refraction index, etc. The quality and the power of the output beam is always affected by these thermal parameters. Having a good estimation of the thermal effects, therefore, is important in design of this lesers kawak. To have a high quality beam, we should study thermal effects, creation of stresses, variation of end surfaces, refraction index, generated in laser to achieve the required accuracy in design of a laser. Having high efficiency and small volume is one of the advantages of pumping by diode laser. Also, by increasing the quality of the pumping process, dissipated heat in laser rod is decreased a lot. This is due to the less amount of quantum displacement when the pumping wavelength and laser wavelength are close. Quantum displacement heats up the laser rod. Because pumping radiation is outside of the absorbtion band of the active ions, the heat emanated by the impurity is removed completely. But, due to the high heat concentration in a small volume, the thermal profile in longitudinally pumped laser crystal becomes highly non uniform and complex. In this paper, we analytically study the thermal effects in a Nd:YAG solid state laser crystal which is pumped in longitude with a second order Gaussian ( super Gaussian) profile. In this survey we neglect z derivatives of temperature distribution and also consider a statement in which thermal condition of cooler system is much more than thermal condition of laser crystal. Then we apply proper boundary conditions to probe thermal distribution function and related thermal effects. It will be shown that use of second order Gaussian profile for output beam of diode lasers is a better approximation for calculating the thermal distribution and estimating the thermal lensing than the Gaussian profile.

P39.

Determination of changes in refractive index and thickness of Si02thin film on polycarbonate created by Vis-IR laser irradiation

'H.Ehsani.A ,2S.Saghafi ,3M.Goraneviss 'Department of physics ,Nur azad university,Nur,Iran 2,3 Biophotonics Group, Plasma-Physics Research Center, Research Science Campus, IAU, Tehran, Iran

The effect of Vis-IR laser irradiation at various energy densities on refractive index and thickness of Si02 thin film onto polycarbonate was reported in this paper. Transmittance spectra were used for determination

98 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) the above characteristics of these films by application of analytical formulas was to the interference extrema. (Swanepoel method). It has been found that the thickness of films decrease by increasing the photon energy of laser and its energy density. It has been observed that the transmittance decreases with the increase of film thickness. From transmittance data, the dispersion of refractive index of sample has been studied. It was found that at high energy density (50.35 J/cm2), the refractive index of sample was more increased. The highest increased in refractive index (An ~ 0.1) was found for sample which irradiated by 532nm laser beam with 50.35 J/cm2 energy density.

P40. Electron self-injection and acceleration in the bubble regime of laser-plasma interaction I. Kostyukov1, E. Nerush1, A. Pukhov2, V. Seredov2 'Institute of Applied Physics, Russian Academy of Science, Uljanova str. 46, Nizhny Novgorod 603950, Russia 2Duesseldorf University, 40225 Duesseldorf, Germany

The intense laser-plasma and beam-plasma interactions are highly nonlinear phenomena, which besides being of fundamental interest, attract a great attention due to a number of important applications. One of the key applications is particle acceleration based on excitation of the strong plasma wakefield by laser pulse [ 1 ]. In the linear regime of interaction when the laser intensity is low the plasma wake is the linear plasma wave. Moreover, the ponderomotive force of the laser pulse pushes out the plasma electrons from high intensity region leaving behind the laser pulse the plasma cavity - bubble, which is almost free from the plasma electrons. This is the bubble regime of the laser-plasma interaction [2], Although the bubble propagates with velocity, which is close to speed of light, the huge charge of unshielded ions inside the plasma cavity can trap the cold plasma electrons. Moreover, the electrons are trapped in the accelerated phase of the bubble plasma field thereby leading to efficient electron acceleration. The electron self-injection is an important advantage of the plasma-based acceleration, which allows to exclude the beam loading system requiring accurate synchronization and additional space. The recent experiments have demonstrated high efficiency of the electron self-injection. The beam quality is often of crucial importance in many applications ranging from inertial confinement fusion to the x-ray free electron lasers. Despite a great interest there is still a little theory for relativistic electron dynamics in the plasma wake in multidimensional geometry including electron self-injection. The dynamics of the self-injected electrons can be roughly divided into three stage: (i) electron scattering by the laser pulse [3], (ii) electron trapping by the bubble [4], (iii) electron acceleration in the bubble. We developed two analytical models for electron dynamics in the bubble field and verify them by direct measurements of model parameters in 3D particle-in-cell (PIC) simulations. The first model is based on a piecewise approximation of the bubble field [5] while the second one uses more realistic distribution of the electromagnetic field inside the bubble. The simulation results are in a good agreement with the model predictions.

Acknowledgments This work has been supported by federal target program "The scientific and scientific-pedagogical personnel of innovation in Russia" and by the Russian Foundation for Basic Research. References [1] T. Tajima and J.M. Dawson, Phys. Rev. Lett. 43,267 (1979). [2] A. Pukhov and J. Meyer-ter-Vehn, Appl. Phys. B 74, 355 (2002). [3] E.N. Nerush and I.Yu. Kostyukov, Phys. Rev. Lett. 103,035001 (2009). [4] I. Kostyukov, E. Nerush, A. Pukhov, V. Seredov, Phys. Rev. Lett. 103, 175003 (2009). [5] I. Kostyukov, E. Nerush, A. Pukhov, V. Seredov, New J. Phys. 12, 045009 (2010).

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P41. Simulation of QED effects in ultrahigh intensity laser-plasma interaction I. Kostvukov, E. Nerush Institute of Applied Physics, Russian Academy of Science, Uljanova str. 46, Nizhny Novgorod 603950, Russia

Due to an impressive progress in laser technology, laser pulses with peak intensity of nearly 2xl022 W/cm2 are now available in laboratory. When the matter is irradiated by so intense laser pulses high energy density plasma is produced. Besides of fundamental interest such plasma is the efficient source of particles and radiation with extreme parameters that opens bright perspectives in developments of advanced particle accelerators, next generation of radiation sources, laboratory modeling of astrophysics phenomena etc. Even high laser intensity can be achieved in the coming large laser facilities like ELI (Extreme Light Infrastructure). At such intensity the radiation reaction and QED effects become important. One of the QED effects, which recently attracts much attention, is the electron-positron plasma creation in strong laser field. The plasma can be produced via electromagnetic cascades: the seeded charged particles is accelerated in the field of counter-propagating laser pulses, then they emit energetic photons, the photons by turn decay in the laser field and create electron- positron pairs. The pair particles accelerated in the laser field produce new generation of the photons and pairs. For self-consistent study of the electron-positron plasma dynamics in the laser field we develop 2D code based on particle-in-cell and Monte-Carlo methods. The electron, positron and photon dynamics as well as evolution of the plasma and laser fields are calculated by PIC technique while photon emission and pair production are calculated by Monte-Carlo method. We simulate pair production in the field of counter-propagating linearly polarized laser pulses. It is shown that for the laser intensity above threshold the plasma production becomes so intense that the laser pulse are strongly absorbed in the plasma. The laser intensity threshold and the rate of laser field absorption are calculated.

Acknowledgments This work has been supported by federal target program "The scientific and scientific-pedagogical personnel of innovation in Russia" and by the Russian Foundation for Basic Research.

P42. Relativistic self-focusing of elliptical laser beam in plasma and its effect on plasma wave and second harmonic generation Keshav Walia1, Arvinder Singh1 ' Department of Physics, National Institute of Technology Jalandhar, India Email id- [email protected]

The present paper investigates the relativistic self-focusing of elliptical laser beam in underdense plasma and its effect on plasma wave and second harmonic generation. When intense laser beam interacts with plasma, then transverse intensity gradient is established on account of redistribution of carriers. This transverse intensity gradients results in generation of plasma wave and pump wave frequency. The generated plasma wave, in turn, interacts with the input laser beam and leads to generation of a second harmonic. Effect of relativistic self- focusing on the amplitude of plasma wave and second harmonic yield are also analyzed.

100 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P43. Enhanced Brillouin scattering of elliptical laser beam in a collisionless plasma Keshav Walia1. Arvinder Singh1 ' Department of Physics, National Institute of Technology Jalandhar, India Email id- [email protected]

This paper presents the Enhanced Brillouin scattering of an elliptical laser beam in collisionless plasma. The transverse intensity gradient of a pump beam generates a ponderomotive force, which modifies the background plasma density profile in a direction transverse to pump beam axis. This modification in density affects the incident laser beam, ion-acoustic wave and back-scattered beam. Non-linear differential equations for the beam width parameters of pump laser beam, ion-acoustic wave and back-scattered beam are set up and solved numerically. Numerical results predict the effect of focusing of waves on the back reflectivity.

P44. Microwave heating of the ceramic materials by the Gaussian maser beam L. Rajaei and B. Shokri Physics Department Qom University, Qom, Iran

The ceramic which has a complex permittivity can absorb electromagnetic energy easily and be heated quickly. In this work, the heating of a ceramic cylinder by the Gaussian electromagnetic beam in two dimensions is investigated and the heat equation is solved. It is shown that this electromagnetic beam with Gaussian profile can heat ceramic sample better than the plane electromagnetic wave. Moreover, the effects of some important physical factors such as the permittivity of ceramic, the incident wave intensity and the spot size of the Gaussian beam on the heat transfer within the sample are studied. Also, comparing the effect of Gaussian electromagnetic beam on ceramics A1203 and, it is shown that A1203 ceramic is heated more intensively than ZnO ceramic.

P45. Electron-positron pairs creation in the field of two strong counterpropagating laser beams and the nonlocality of the photon-photon interaction R. Kh. Gainutdinov, M. A. Khamadeev. A. A. Mutygullina Department of Physics, Kazan Federal University, 18 Kremlevskaya St, Kazan 420008, Russia

We discuss various approaches to problem of the electron-positron pair creation in the strong external field. Special interest presents the circuit, in which the interaction of two strong counterpropagating laser beams in vacuum is considered. For the calculation of the probability of the creation the following formula is usually applied [1]:

E H) W = 2 \m(d, ' (pL )) =

2 / jg = m where Pi EL jEcr and Ecr = / = 1.3 • 10 V/cm is the Schwinger field limit. However this expression was obtained even in pioneer works dedicated to vacuum nonlinearity [2] and it based on some approximations. Attempt of the strict analysis has been made in work [3] by introducing the nonlocal form- factor into the Lagrangian. But, as it is well known, such procedure leads to the loss of Lorenz invariance or unitarity. We show that the formalism of generalized quantum dynamic (GQD) [4] opens new opportunities to solve such problems. We show also how it can be made proceeding from nonlocal interaction operator obtained earlier within the framework of the formalism of GQD.

101 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters

Acknowledments: this work was supported by the Grant of Federal Agency on Education, Russia (Contract number 02.740.11.0428) and by the Grant of Russian President No. NSh 2965.2008.2. References [1] N. B. Narozhny et al., JETP 102, 9 (2006) [2] J. Schwinger, Phys. Rev. 82, 664 (1950) [3] A. Di Piazza et al., Phys. Rev. D 72, 085005 (2005) [4] R. Kh. Gainutdinov, J. Phys. A 32, 5657 (1999)

Marat Khamadeev: [email protected]

P46. Simple characterization method for foams and aerogels of gas-like densities Borisenko L.A.1. Shapkina N.E.1 ' Faculty of Physics, M. V.Lomonosov Moscow State University, Leninskie Gory 119991, Moscow, Russia

Low-density solids are of interest for target application in ICF and are widely used in laser and in particle beams interaction experiments at present. The densities achieve as low as 1-2 mg/cc, which is comparable to that of the air at normal conditions. The solid material done as foam or as aerogel with density comparable to that of gas is difficult to measure, owing to the poor optical density, especially in thin layers. The soft x-rays characterization was reported earlier as non-destructive method for laser targets with such layers. Here we used an optical microscopy where the object with the foam or aerogel part was illuminated by the lasers of 2 additional wavelengths and/or by white light. For measurements of refractive index the macroscopic samples were needed and used. Then by microscopic study we could report the difference between 100-micron foam/aerogel (optically transparent) layer and thin film of the same material hidden inside washer, between varying densities of the samples with similar structure, and those of the same areal mass. Foams or alternatively aerogels can be formed from certain polymers depending on the fabrication route. The light scattering in foam structure is found capable of mixing the 2 beams of additional colors throughout the material volume, whereas in aerogel structures the mixing takes place in the beam intersection only. Considering independent scatters in the aerogel, the measured signals are compared to the simulated Mie scattering in the material. The nanoparticles of metal inserted into aerogel could be detected through optical scattering. But we failed to register nanoparticles in foams by detecting the scattered signal as in aerogels. Optical characterization procedure for highly transparent objects, including nanostructured microobjects, is proposed to prepare the targets for laser shots. References [1] Khalenkov A.M. et al, 2006, Laser&Particle Beams, 24, 283

P47. Collective modes of laser excited electrons in clusters H. Reinholz1. T. Raitza2, G. Ropke2 and I. Morozov3 'Johannes-Kepler-Universtitat Linz, Institut fur Theoretische Physik, Linz (Austria) 2University of Rostock, Institute of Physics, Rostock (Germany) 3Joint Institute for High Temperatures of RAS, Moscow (Russia)

Clusters of material at solid state densities can form nanoplasmas after intense laser irradiation. The time evolution of the electron ion system is simulated using semi classical molecular dynamics (MD) simulations. Plasma properties like temperature and density are discussed as function of time [1].

102 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

In order to investigate dynamical correlations for finite systems the method of restricted MD simulations has been developed [2]. In this context, we investigate the bi-local frequency dependent structure factor for excited clusters. Within the resonance structure found, different collective excitations have been identified and characterized via the spatial distribution of the momentum auto-correlation function. For demonstration of the applicability of restricted MD simulations, results for resonances in a linear ID chain are discussed [3]. A systematic behaviour of a dispersion relation typical for plasmon excitations is obtained and agrees well with the bulk limit of an infinite chain. Collective electron excitation modes of 3D clusters are analysed using spherical harmonics. The spatially resolved momentum auto-correlation spectrum is interpreted in terms of collective electron excitation modes. Resonance frequencies of the modes are calculated and identified, for instance as a rigid collective oscillation of all electrons as well as a plane wave like oscillation. Damping rates are discussed. In order to compare with bulk properties, size effects of dynamical properties are investigated. Comparing different cluster sizes at similar ionization degrees, temperatures and densities, we found systematic changes for the Mie mode and the bulk plasmon excitations. In particular, the damping rates are increasing with the cluster size. As already shown for bulk plasmas, the dynamical bi-local structure factor, in particular the current autocorrelation function, is related to optical properties. Scattering as well as absorption of light in excited clusters is influenced by the corresponding collision frequency [4] and subsequently affects the dielectric response function. References [1] T. Raitza, H. Reinholz, G. Ropke, I. Morozov, and E. Suraud; Contrib. Plasma Phys. 49, 498 (2009). [2] T. Raitza, H. Reinholz, G. Ropke, and I. Morozov; J. Phys. A 42, 214048 (2009). [3] T. Raitza, H. Reinholz, and G. Ropke; J. Mod. Phys. B accepted (2010). [4] H. Reinholz; Ann. Phys. Fr. 30, No 4 - 5 (2006).

P48. Consistent inclusion of radiation reaction into kinetic plasma modeling Nina Elkina and Hartmut Ruhl Computational and Plasma Physics, Ludwig-Maximilians-University, Theresienstrasse 37, 80333 Munich, Germany

Radiation properties of laser plasma and the resulting collective effects due to the radiation reaction force are relevant for the most powerful lasers interacting with matter available in the laboratory today. The contribution of the radiation reaction force to the total force acting on a charged particle moving in plasma is analyzed. Radiation is principally included in the standard calculation of self-consistent fields. Since the high frequency part of the emitted radiation cannot always be resolved in numerical simulations due to a finite time step one can think to include radiation reaction using a consistent physical model. For these purposes we have derived a modified kinetic equation which describes the radiation damping as a result of non-Hamiltonian dynamics in phase space due to the interaction with radiation. We use this equation for the derivation of moment equations for macro-particles. As physical models for the radiation force we use the classical Lorentz-Abraham-Dirac (LAD) and the Landau- Lifshitz equations derived from LAD. Both models are incorporated into a large scale Particle-In-Cell code to treat the radiation self-action in the classical validity range, i.e. when the recoil energy of scattered photons is not too big in comparison with the energy of the interacting electron. The model has clear advantages for the treatment of coherent effects in laser field-plasma interaction. We also discuss consistent matching with a more elaborated semi-classical radiation model. The model has no limit for the recoil energy but suffers from a lack of coherence. Both models have to be used together to simulate multi-scale processes of electron acceleration, highly brilliant X-ray sources and QED effects [1], which may become important in the course of the ELI project.

103 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters

Acknowledgements: This work has been funded by the Munich Centre of Advanced Photonics. References [1] A. I. Nikishov and V. I. Ritus, Quantum Processes in the field of a plane electromagnetic wave and in a constant field, SOVIET PHYSICS JETP, 19 (1964).

P49. Higher harmonic generation through laser produced plasma S.C. Singh National Centre for Plasma Science and Technology (NCPST) Dublin City University, Dublin-9, Ireland E-mail: [email protected]

Generation of Extreme UV (EUV) coherent light sources i.e. EUV lasers are highly demanded in order to continue the validity of moore's law in future, high density data writing on the disks, material synthesis and characterizations, spectroscopic investigations etc. High order harmonic generation (HHG) may be presentably considered the simplest and most efficient way for producing ultra-short laser radiation in the broad spectral range of EUV/VUV radiation. Other ways of obtaining radiation in this spectral range are X-ray and free electron lasers. X-ray lasers have narrow spectral range of operation with poor spatial coherence and radiation divergence, while free electron lasers are less popular due to their high cost. Several methods such as interaction of intense laser pulses with gases, with low electron density laser produced plasma, and by the reflection of relativistic high intensity laser pulses from solid surfaces, are available these days. HHG conversion efficiency can be enhanced by (a) increasing phase matching conditions (b) using the resonance of atomic/ionic transition for particular harmonic (c) periodic modulation of atomic density in nonlinear medium (d) exploiting clusters of atoms/molecules, which can enhance recombination probability of oscillating electrons with their parent nuclei and (e) employing Surface Plasmon Resonance of nanostructured materials for small order harmonics. Recent developments of HHG through laser produced plasma on the surface of solid target will be explored in this presentation. Exploitation of phase matching conditions, injection of nanoparticles in the plasma, and use of atomic and molecular clusters for enhancing harmonic efficiency and cutoff will be also presented. Effect of electron density and temperature of the plasma, pulse width of the main pulse, time delay between pre and main pulses on the harmonic efficiency and cutoff is also subject of present work.

P50. Optical Emission Spectroscopic Study of Laser Induced Zinc and Cadmium Plasma 12 S.C. Singh, 2R. Gopal 'National Centre for Plasma Science and Technology, Dublin City University, Dublin 9, Ireland 2*Laser Spectroscopy & Nanomaterials Lab., Department of Physics, University of Allahabad, Allahabad-211002, India

Laser induced plasmas (LIP) formed on the surface of solid target, have acquired great interest in recent times as EUV/XUV, visible, IR light, electron, X-ray and ion sources. Electron density, electron and ion temperatures of nanosecond laser produced zinc and cadmium plasmas are investigated using optical emission spectroscopy (OES) study of atomic lines. In a typical experimental procedure, laser light (1064, 532 and 355 nm) at different laser irradiances from the Q-switched pulsed Nd:YAG with 6- 10 ns pulse widths and 10 Hz repetition rate was focused on the high purity Zn/ Cd targets ( 99.99 %, Specpure, Johnston Mathey, U.S.A.) using a 20 cm focal length convex lens for ablation and plasma processing in air. The radiation emitted from each metal plasma was focused onto the tip of an optical fiber bundle, mounted at the right angles with the direction of the plasma expansion via a small collecting lens. A QE65000 spectrometer with Hamamatsu S7031-1006 CCD

104 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

detector system was used tp record the optical emission after a delay of 500ns. Electron density was measured using Stark broadening of the atomic lines, while the intensity ratio of two atomic lines of the same species was utilized for temperature measurement. Ratio of neutral and ionic lines is used for the investigation of ionic temperature.'

200 Waveelngth (nm)

Fig. 1 Optical emission spectra from the zinc plasma produced by laser ablation of zinc rod in air using 1064 nm of Nd: YAG laser at different laser irradiances

P51 FST-formation of cryogenic layer inside spherical shells of HiPER-class: results of mathematical modeling and mock-ups testing A.A.Belolipetskiy1, E.R.Koresheva2,I.V.Aleksandrova2, A.N.Aleksandrov3, E.L.Koshelev2, V.A.Kalabuhov2, E.A.Malinina1,1.E.Osipov2, L.V.Panina4, A.I.Safronov^ K.O.Semenov1, T.P.Timasheva2,1.D.Timofeev5, G.S.Usachev5 'A.A.Dorodnitsin Computing Centre of Russian Academy of Sciences, Moscow, Russia 2RN.Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia, 3Corporation "CONSYST", Moscow, Russia 4Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia 5Federal State Unitary Enterprise "Krasnaya Zvezda", Moscow, Russia

Current stage in the IFE research has passed to a closing stage: creation of the experimental reactor and realization of electric power generation. HiPER is a proposed European High Power laser Energy Research facility dedicated to demonstrating the feasibility of laser driven fusion for IFE reactor. The HiPER facility operation requires the formation and delivery of spherical shock ignition cryogenic targets with a rate of several Hz. The targets must be free-standing, or un-mounted. At the Lebedev Physical Institute (LPI), significant progress has been made in the technology development based on rapid fuel layering inside moving free-standing targets which refers to as FST layering method. It allows one to form cryogenic targets with a required rate. In this report, we present the results of a feasibility study on high rep-rate formation of HiPER-class targets by FST. We consider two types of the baseline target for shock ignition. The first one (BT-2) is a 2.094-mm diameter compact polymer shell with a 3-pm thick wall. The solid layer thickness is 211 pm. The second (BT-2a) consists of a 2.046-mm diameter compact polymer shell (3-pm thick also) having a DT-filled CH foam (70 pm) on its inner surface, and then a 120 pm-thick solid layer of pure DT. The work addresses the physical concept, and the modeling results of the major stages of FST technologies for different shell materials:

105 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary ) c Abstracts - posters

• Filling stage optimization (computation): optimal filling of a target batch up to ~ 1000 atm at 300 K requires minimizing the diffusion fill time due to using the ramp filling method for both BT-2 and BT-2a. • Depressurization stage optimization (computation and experiments): it requires providing the shell container leak proofness during the process of its cooling down to a depressurization temperature. This allows one to fulfill the technical requirements on the risks minimization associated with the damage of the HiPER-class targets. • Layering stage optimization (computation and experiments): 1-st step requires (a) choosing an optimal temperature of target input into the layering channel, (b) analyzing the "liquid- vapor" interface behavior at different cooling rates, and (c) computation of the FST layering time. • A preliminary consept of the FST-lavering module for HiPER-class targets (including the interface unit for target-and-sabot assembly) is presented. The results of the mock-ups testing are disscussed, namely: (a) FST layering channels (LC) of different geometry have been created and the time of target residence inside LC has been measured for 2 mm diam. targets of different weight and material, including a HiPER-class sur- rogate target. This allows determining the requirements on the LC manufacturing. (b) Mock-up of target positioning device has been constructed and tested. It was found that the device ensures a comprehensive look at the target for the time less than 1 sec. Acknowledgement This work supported by the International Science and Technology Center (ISTC) under contract N«3927 (Partner of the project is Science and Technology Facilities Council (STFC), UK)

P52. Fast electron transport in shaped solid targets Anle Lei^.L. H. Cao4, K. A. Tanaka2, R. Kodama2, X. T. He4, K. Mima5, T. Nakamura5, T. Norimatsu5, W. Yu1, and W. Y. Zhang4 1Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China 2Institute of Laser Engineering and Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan 3Forschungszentrum Dresden-Rossendorf, 01328 Dresden, Germany 4 Institute of Applied Physics and Computational Mathematics, Beijing 100088, China institute of Laser Engineering, Osaka University, Osaka 565-0871 Japan

The scheme of fast ignition fusion energy relies on the ultra-intense ultra-short (UIUS) laser energy transport into the compressed core plasma. One solution is to insert a hollow cone in the fuel shell to block the UIUS laser from the coronal plasma, thus allowing it to reach the core plasma. The cone not only can guide the UIUS laser to its tip, but can play important roles in the specific cone-in-shell target designed for FI. It was found in a PIC simulation that the cone can guide the fast electrons generated at the inner wall to propagate along the wall surface toward its tip, which would increase the energy density at the tip and might enhance the heating of the core plasma. Surface guiding of fast electrons with planar foil targets has been demonstrated experimentally. However, the guided fast electrons will mix the electrons generated ahead by the laser light with a planar target, and hence one cannot experimentally quantitatively validate the guide of the fast electrons. We investigate the cone guiding of fast electrons with an inverse cone target. We found a novel surface current of fast electrons propagating along the cone wall. The fast electrons generated at the planar outer tip of the inverse cone are guided and confined to propagate along the inverse cone wall to form a surface current by induced transient electric and magnetic fields associated with the current itself. Once departing from the source at the outer tip, this surface current of fast electrons is "clean", neither experiencing the interacting laser light nor mixing fast electrons ahead, unlike those in cone or planar targets. This surface current in the inverse cone may explicitly give the capability of the guide of fast electron energy by the cone wall. The guiding and confinement of fast electrons is of importance for fast ignition in inertial confinement fusion and several applications in high energy density science.

106 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P53. Low velocity ion slowing down in a demixing binary ionic mixture Claude Deutsch1, Daniel Leger2 and Bekbolat Yashev3 1 Universite Paris-Sud, LPGP (UMR-CNRS 8578, Bat. 210, F-91405 ORSAY, France 2Universite Valenciennes-Hainaut Cambresis,Lab. MECAN, F 59313 MONTHOUY, France ^Kazakh National University, Department of Physics, Tole Bi 91, 4800012 ALMATY, Kazakhstan.

We consider ion projectile slowing down at low velocity Vp < Vthe, target thermal electron velocity, in a strongly coupled (Gamma~60) and demixing hydrogen-helium ionic mixture of astrophysical concern. It is investigated in terms of quasi-static and critical charge-charge structure factor for each ion species out of the HNC-scheme. Non-polarizable as well as polarizable partially degenerate electron background are given attention. The given low velocity ion slowing down turns negative in the presence of long wavelength and low frequency hydrodynamic modes, signalling a critical demixtion. This superelastic process thus documents an energy transfer from the target ion plasma to incoming ion projectile.

P54. The production of advanced fast ignition cone geometries for fusion studies C. Spindloe Scitech Precision Ltd, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot, Oxon, UK Contact: [email protected]

The recently launched HiPER (High Power laser Energy Research facility) project is a European initiative to offer a credible way to demonstrate the possibility of opening up Inertial Fusion Energy as a commercial process for energy generation. One baseline target design includes cone geometries and there are significant technical and scientific challenges in the production of these cones to the required specification in the required numbers for the facility. There are also a large number of research projects that are investigating cone performance and are re-designing the cone to have novel features and specifications. We review the production of a number of different geometries and also the ability to mass produce such items.

P-55. Ignition and burn in contaminated DT fuel at high densities John Pasley University of York and STFC Central Laser Facility, U.K.

Radiation hydrodynamics simulations have been performed to quantify the effect of contamination upon the ignition threshold in DT at high densities. A detailed thermonuclear burn model, with multi-group multispecies ions, is incorporated alongside a multigroup diffusion approximation for thermal radiation transport. The code used is the research version of the HYADES ID code [1], Acceptable levels of contamination are identified for a range of contaminant ion species. A range of different contaminant spatial distribution within the fuel are explored: i) in which the contamination is uniformly distributed throughout the fuel ii) in which the impurity ions are confined to the hotspot, or iii) where contamination is restricted to a particular region of the hotspot (either centrally, near the surface, or at an intermediate location). Initially the fuel has a constant density with the hot-spot located centrally. The overall radius of the fuel is chosen to be sufficiently large that it has no significant effect upon the success or failure of ignition. The evolution of the system is then simulated until ignition either establishes widespread thermonuclear burning, or a failure to ignite is observed. The critical pr for ignition is found by iteration on the hot-spot radius. We show that varying the spatial distribution of the contaminant within the ignition spot has little effect, so long

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 107 c Abstracts - posters ) as the total mass of contaminant is held the same. As expected, high-Z contamination is far more detrimental than that by low-Z ions. Discussion of the findings in the context of re-entrant cone-guided fast ignition is presented, in addition to a theoretical interpretation of the results. Reference [1] contact [email protected]

P-56. Laser fusion energy from p-7Li with minimized radioactivity M. Ghoranneviss1, B. Malekynia1, H. Hora2, G.H. Miley3, A. H. Sari14 'Plasma Physics Research Center, Science and Research Campus, Islamic Azad University (LAU), Tehran, Iran. 2Department of Theoretical Physics, University of New South Wales, Sydney 2052, Australia 'Department of Nuclear, Plasma and Radiological Engineering, University of Illinois, Urbana, IL 61801, USA 4 Faculty of Engineering, Kingston University, London SW15 3DW, UK

The observed anomaly of PW-ps laser interaction opened the possibility of the side-on ignition of solid DT [1] and the updating led to encouraging results [2] for DT laser fusion within comparably compact reactors in the future. The new possibility of side-on laser ignition of p-nB with negligible radioactivity encouraged to study the fusion of solid state p-7Li fuel which again turns out to be only about ten times more difficult than the side- on ignition of solid deuterium-tritium using petawatt-picosecond laser pulses very close to the case of p-"B [2-5]. It was interesting to check another candidate for a safe, low cost and comparably clean nuclear power generation from the reaction of p-7Li fuel. The result for p-7Li under the simplified and pessimistic conditions are reported. Updated cross sections of the nuclear reaction are included. We derived that the threshold for the side-on ignition for the energy-flux density with an ignition temperature is merged into a constant value of 2.5xl09 J/cm2 and 69 keV, respectively. It can be concluded that this result of not too much higher difficulty for the clean fusion energy generation than for DT fuel can be stated with certainty. This does not depend on minor modifications and corrections from further studies of numerous details to be gained in further studies. One modification may be due to the fact that the ignition temperatures for all the considered fuel are above the energy loss by bremsstrahlung as known since the computations for DT [ 1 ] and as it was repeatedly confirmed in the present treatments. However, this emission was based on thermal equilibrium functions with the fusion cross sections averaged over a Boltzmann distribution of the electron velocity. The side-on ignition is a process in a shock front with energy production from the ions and the generated alpha particles. It may well be that the Boltzmann distribution is strongly disturbed and only details with the PIC method or what was gained from the "peripheric ignition" may lead to more detailed evaluations apart from several more parameters to be studied. A distinguishing is necessary between the double layer processes defined by internal electric fields in plasmas known form the genuine two-fluid computations determining the TNSA and between physically different skin- layer mechanisms which are optically determined by dielectrically increased blocks or skin depths. We have studied the change of the results when using the collective stopping power in contrast to the usually used binary collision stopping of the Bethe-Bloch theory. In contrast to the cases with DT with a strong dependence on the stopping power model with changes of the temperature of the ignition threshold by few keV, a similar difference for p-7Li is again by a few keV but this is comparably small in view the rather high ignition temperature of 69 keV. Reference [1] M.S. Chu, Phys. Fluids 15, 412 (1972) [2] H. Hora, J. Badziak, Phys. Plasmas 14, 072701 (2007) [3] H. Hora, Laser and Particle Beams 27, 207 (2009) [4] H. Hora, G.H. Miley, M. Ghoranneviss, B. Malekynia and N. Azizi, Optics Communications 282,4124 (2009)' [5] H. Hora, G.H. Miley, M. Ghoranneviss, B. Malekynia, N. Azizi and Xian-Tu. He, Energy Environ. Sci., 3,479 (2010).

108 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-57. Analysis of effects of laser profiles on fast electron generation by two-dimensional Particle-In-Cell simulations M. Hata1, H. Sakagami2, T. Johzaki3, A. Sunahara4, H. Nagatomo3 'Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan 2Department of Simulation Science, National Institute for Fusion Science, Toki, Gifu, 509-5292, Japan 3Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan 4 Institute for Laser Technology, Suita, Osaka, 565-0871, Japan

A cone-guided target is used in the Fast Ignition Realization Experiment project phase-I (FIREX-I) [1] and optimization of its design is performed. However a laser profile is not optimized much, because the laser profile that is the best for core heating is not known well. To find that, it is useful to investigate characteristics of generated fast electrons in each condition of different laser profiles. In this research, effects of laser profiles on fast electron generation are investigated on somewhat simple conditions by two-dimensional Particle-In-Cell simulations. In these simulations, a target is made up of Au pre-plasma and Au plasma. The Au pre-plasma has the exponential profile in the x direction with the scale length L = 4.0 pm and the density from 0.10ncr to 20ncr. The

Au plasma has the flat profile in the x direction with 10 pm width and 20ncr. Plasma profiles are uniform in the y direction. The ionization degree and the mass number of plasmas are 40 and 197, where the ionization degree is determined by PINOCO [2] simulations. PINOCO is a two-dimensional radiation hydrodynamics simulation code, which simulates formation of the high-density plasma during the compression phase in the fast ignition. A laser is assumed to propagate as plane wave from the negative x direction to the positive x direction. Laser profiles are supposed to be uniform in the y direction. Three different laser profiles, namely flat one with t„ =

100 fs, Gaussian one with trjsc/fall = 47.0 fs and flat + Gaussian one with trise/M = 23.5 fs and t„ = 50 fs are used. 7 2 20 2 The energy and the peak intensity are constant with E = 10 J/cm and IL = 10 W/cm in all cases of different laser profiles. We compare results in each condition of three different laser profiles and investigate effects of laser profiles on fast electron generation. Time-integrated energy spectra are similar in all cases of three different laser profiles. In the case of the short pulse, effects of laser profiles are small. We will discuss details in this case, results in the case of the long pulse of which the duration is grater than 500 fs and optimization of the laser profile. References [1] H. Azechi and the FIREX Project, Plasma Phys. Controlled Fusion 48, B267 (2006). [2] H. Nagatomo et al., Proc. of 2nd Int. Conf. on Inertial Fusion Science and Applications 2001 (Kyoto, Japan, 9-14 September 2001) (Amserdam:Elsevier) pp 140-2 (2002).

P-58. He3-He3 fusion energy with negligible radioactive emission by block ignition with petawatt-picosecond laser pulses N. Azizi1. B. Malekynia2, M. Ghoranneviss2, A. Mohammadian2, M. Kouhi2 .Z.Abdollahi2 H. Hora3, G.H. Miley4, 'Islamic Azad University, Khoy Branch; 2Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran-Poonak, Iran; department of Theoretical Physics, University of New South Wales, Sydney 2052, Australia; department of Nuclear, Plasma and Radiological Engineering, University of Illinois, Urbana 61801, USA

A new way for generation of low-cost, safe, clean and unlimited nuclear fusion energy with negligible dangers from radioactive radiation may have been opened by the recent development of Petawatt-picosecond laser pulses. However, only the very rare experiments with extreme suppression of pre-pulses arrived at the effect to suppress relativistic self-focusing. Subsequently, dominant nonlinear force driven plasma acceleration of

109 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters 3 highly directed plasma blocks of modest temperature and ultra-high ion current densities above 10" Amps/ cm2 were measured in agreement with earlier derived theory. This permits side-on ignition of solid density fusion fuel explored at 1970 by Chu and Bobin. After now available multi-petawatt laser pulses may lead to low cost ignition of deuterium-tritium, it was found that surprisingly easy ignition of proton-boron 11 is possible in strong contrast to the impossibility with ignition by spherical laser compression. The extension of these computations for igniting helium-3 of solid state density is reported comparison with the usual laser fusion schemes.

P-59. The role of finite instrumental resolution scales in plasma modeling Minkova N.R.1 1 Tomsk State University, FTF, Lenin Ave., 36, Tomsk, 634050, Russia

By comparing theoretical results and experimental data (as well as data of observations and model experiments) we have to provide similar conditions for investigated processes and their adequate modeling . One of such factors is finiteness of instrumental resolution scales that restricts our ability to measure particles' coordinates. The consideration of this restriction generates multiparticle statistical approach to modeling of plasmas as systems with long-range interparticle interactions (e.g. [1,2]). This model operates with probability distribution function of macroscopic parameters' fluctuations. The mentioned approach is presented in the paper for collisional and non-collisional plasmas and its application to the solar wind. The dimension of statistical model (corresponding distribution function) depends on number of particles within a probing volume (on a resolution scale) and can be reduced to values determined by scales of interparticle interaction. Under some assumptions this reducing process can lead to kinetic models of lower dimension. For instance, to a two-particle kinetic model for proton-electron (two-component) plasma. The application of the discussed approach to description of collisional plasma results mostly in increasing of model's dimension. The presented approximation reproduces specific features of solar plasma's parameters (density, speed, velocity distribution function, etc.) and yields results that are consistent with observations (e.g. [3]). References [1] N.R. Minkova Izvestiya vuzov. Physics. 47, No.10 (Special issue) 73-80 (2004) (in Russian). [2] N.R. Minkova Contrib. Plasma Phys. 49, No. 1-2, 90-97 (2009) [3] E. Marsch, Kinetic physics of the solar wind plasma in Physics of the Inner Heliosphere. Heidelsberg, Spring-Verlag, 1991.

P-60. Calculations of multielectron-ion atomic data and opacities of hot dense plasmas and relevant database developments S.V. Gagarin1, M.V. Kobel'kova1, S.V. Koltchugin1, P.A. Loboda^S.V. Morozov1, V.V. Popova1, A.A. Shadrin1,1. Yu. Silantieva1,1.V. Solomina1,1.A. Vaninaj M.A. Vorobyova1, A.Ya. Faenov2, A.I. Magunov2, T.A. Pikuz2,1.Yu. Skobelev2,1.L. Beigman13, F.F. Goryaev13, A.M. Urnov13,1.Yu. Tolstikhina13, L.A. Vainshtein13 'Russian Federal Nuclear Center - All-Russian Institute of Technical Physics (RFNC-VNIITF), 13, Vasilyeva St., Snezhinsk, Chelyabinsk region, 456770, Russia 2Joint Institute for High Temperatures of Russian Academy of Sciences (JIHT ofRAS) 13/19, Izhorskaya St., Moscow, 125412, Russia 3P.N. Lebedev Physical Institute of Russian Academy of Sciences (FIAN) 53, Leninsky ave., 119991, Moscow

Modeling of radiative properties of matter in various problems of high energy density physics calls for reliable and systematic theoretical data on the monochromatic and averaged opacities of hot, dense plasmas in broad

110 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters

temperature and density ranges. Calculations of those, in turn, imply realistic description of atomic data of various ions — information on the fundamental properties of electronic structure of atomic systems and related elementary processes. The relevant data also form the basis for upgrading high-resolution diagnostic tools in the studies of high-energy-density physics and astrophysics as well as for the development of ultrabright tabletop sources of x-ray and extreme-ultraviolet radiation requested by many technological and scientific applications. The paper presents a brief overview of activities being run at RFNC-VNIITF to generate atomic data with up- to-date codes, calculate monochromatic and averaged opacities of hot, dense plasmas, and maintain those with special-purpose databases. Acknowledments The work has been supported in part by the International Science and Technology Center under the projects # 3504, 3755 and by the VAMDC project funded under the "Combination of Collaborative Projects and Coordination and Support Actions" Funding Scheme of The Seventh Framework Program (Call topic: IN- FRA-2008-1.2.2 Scientific Data Infrastructure. Grant Agreement number: 239108).

P-61. Equations of state and melting of metals under intense ultrashort laser influences K. V. Khishchenko Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg2, Moscow 125412, Russia

Multiphase equations of state for structural materials are necessary for numerical simulations of processes of pulsed influences on condensed media. A substance irradiated by ultrashort laser pulses behaves as a two- temperature system of electrons and heavy particles (atoms, ions and nuclei). In this work, an equation-of-state model for metals is suggested allowing for the melting and evaporation in the two-temperature case. Equations of state for titanium, iron, zinc and some other metals are developed. As distinct from the previously obtained multiphase equations of state for metals [1], new functional expressions for thermodynamic potentials are formulated. Those provide for a more correct taking into account melting effects and thermal contribution of heavy particles in the liquid phase under rarefaction [2-4], A critical analysis of calculated results is made in comparison with available experimental data for the metals at high energy densities. References [1] V. E. Fortov, K. V. Khishchenko, P. R. Levashov and I. V Lomonosov, Nucl. Instr. Meth. Phys. Res. A 415,604 (1998). [2] M. E. Veysman, M. B. Agranat, N. E. Andreev, S. I. Ashitkov, V. E. Fortov, K. V. Khishchenko, O. F. Kostenko, P. R. Levashov, A. V. Ovchinnikov and D. S. Sitnikov, J. Phys. B: At. Mol. Opt. Phys. 41, 125704 (2008). [3] M. E. Povarnitsyn, K. V. Khishchenko and P. R. Levashov, Appl. Surf. Science 255, 5120 (2009). [4] M. E. Povarnitsyn, T. E. Itina, K. V. Khishchenko and P. R. Levashov, Phys. Rev. Lett. 103,195002 (2009).

P-62. The velocity measurement of shocks generated by x-ray radiation in different materials at "Iskra-5" laser N.V. Zhidkov, V.V. Vatulin, A.G. Kravchenko, P.G. Kuznetsov, D.N. Litvin, V.V. Mis'ko, A.V. Pinegin, N.P. Pletenev, A.V. Senik, K.V. Starodubtsev, G.V. Tachaev Russian Federal Nuclear Center VNIIEF, 607190, Sarov, Nizhniy Novgorod reg,Russia

The results on the development of shock velocity measurement in the samples from different materials at "Iskra-5" laser are presented. The researched samples were irradiated by X-ray radiation of the box-converter, the shock velocity was determined by the moment of its appearance at the sample rear surface. The UV radiation of rear surface induced by shock was registered by streak camera. The theoretical analysis of the experiments on X-ray radiation interaction with materials and gas-dynamic processes in samples was carried out. The range of measured shock velocities in the experiments was D=8 + 45 km/s. The range of X-ray temperatures determined by the shock velocity measuring in Al was T~140h- 170 eV.

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 111 c Abstracts - posters D

P-63. The EOS studies on Luch facility Bel'kov S.A.,Voronich I.N., Garanin S.G., Derkach V.N.. Kochemasov G.G., Litvin D.N., Sukharev S.A. ILFI, RFNC-VNIIEF, Sarov, Russia

The results of the investigations in the shock compressibility of materials on the "Luch" facility [ 1 ] are presented. The experiments have been performed with impedance mismatch technique [2] applying. The output non-uniformity of the shocks achieved <10ps and inaccuracy of their velocity measuring <3%. The pressures to 30 Mbars were developed in lead and till 30 Mbars with applying of the special-constructed targets for hydrodynamic pressure increasing. Results on the materials shock compressibility have been obtained that accord well with the test results shown on hydrodynamic stands [3],

The work was performed in part under the sponsorship of the RFFI (grants No.09-02-12157-ofi_m and No.09- 02-97089-r_povolzh'ye_a), and grant of the President of the RF to leading scientific schools No.65192.2010.2 References: [1] S G Garanin, A I Zaretskii, RI Il'kaev, G A Kirillov et al. Quantum Electronics, v. 35, Na4, p. 299 (2005). [2] Zel'dovich Y.B. & Raizer Yu.P. Physics of shock waves and high temperature hydrodynamic phenomena. New York: Academic Press (1976). [3] Experimental data on shock-wave compression and adiabatic expansion of condensed matter. Edited by R.F. Trunin, Sarov (2001).

P-64. Development of the systems for uniform target irradiation Voronin A.Yu., Garanin S.G., Derkach V.N., Zhidkov N.V., Kravchenko A.G., Petrazhitskaya N.A., Starodubtsev K.V., Sukharev S.A., Shnyagin R.A. ILFI, RFNC-VNIIEF, Sarov, Russia

The new devices have been developed for laser beams homogenizing in the focal spot - multi-component lens raster and raster with the edges smoothing phase mask [1]. The envelope non-uniformity of <3-5% at energy concentration up to 60% was achieved for beams having the initial non-uniformity in the near field of approximately 30% and divergence < 10 " radians. Investigation into the temporary-spatial smoothing with the use of low-density foams with the density less than the critical one [2] is still in progress. Experiments on the foams with the density of 1-2.3 mg/cm3, thickness of 100-200 (im, and the cells' sizes up to the tens of micrometers were carried out with the radiation wavelength of 0.657 pm. The RMS non-uniformity <5% has been found for the beam passed through the foam. The non- uniformity is evenly distributed over the spatial frequency spectrum. The induced divergence of radiation is measured to be 0.35radian. The frequency of the rearranged speckled field of about 2 THz was obtained. The beam smoothing was recorded from the start of pulse of radiation, had the duration up to 1 ns, and the width of the radiation spectrum was about 30 A. The work was performed in part under the sponsorship of the RFFI (grants No.09-02- 12157-ofi_m and No.09- 02-97095-r_povolzh'ye_a), and grant of the President of the RF to leading scientific schools No.65192.2010.2. References: [1] V.N.Derkach, S.G.Garanin, A.V.Kravchenko et al. Proceedings of XXIX ECLIM, Madrid, 707 (2006). [2] S.G. Garanin, V.N. Derkach, R.A. Shnyagin. Quantum Electronics, v. 34, Ne5, p. 427 (2004).

112 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-65. Flux of multiple charged metal ions from plasma of a low voltage laser-induced vacuum discharge I.V.Romanov1, A.A.Rupasov1, A.S.ShikanovW.L.Papernv2. A.Moorti3, R.K.Bhat3, P.A.Naik3, P.D.Gupta3 1 P. N. Lebedev Physical Institute, 53 Leninsky Prospect, Moscow 119991, Russia 2 Irkutsk State University, Irkutsk 664003, Russia 3 Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India

The process of ions emission from the plasma of the fast laser-induced vacuum discharge has been studied experimentally. Parameters of the discharge with the aluminum cathode were as follows, current amplitude was up to 1.7 kA, current rise rate was near 7.5x10® A/s and the capacitor voltage was of 2.3 kV. The discharge has been induced by the laser pulse with duration 30 ps, energy less than 10 mj and power density of 5x 10" W/cm2 which irradiates the cathode. The discharge was shown to be an effective source of accelerated and highly charged ions of the cathode material. The aluminum ions production has been observed definitely at the instant when the discharge current rise rate attains its peak and the plasma pinching occurs at the front of the cathode jet expanding into the inter- electrode gap. Ion energy distributions were characterized by the presence of a significant non-Maxwellian tail of the accelerated ions. The typical maximum ion charge and energy per a charge unit were equal to +8 and 14 keV/Z, respectively. The energy of ions exceeded the potential of current source for the value of not less than 5Z times. The performed qualitative analysis of ion beam characteristics under the conditions of initiating laser pulse energy variation has shown that formation of the micro-pinch structures in the cathode plasma jet (achievable by means of optimizing the laser pulse energy) enhances the maximum charge of the beam ions. The exceeding of average energies of the ions emitted from the discharge plasma over the average energies of ions emitted from the laser produced plasma (without discharge) under the essentially more powerful laser irradiation of aluminum target (27 ps, 400 mj, 2xl013 W/cm2) has been shown. Furthermore, discharge ions energies are comparable with the maximum ion energies observed in this kind of laser produced plasma. Acknowledgements The work was supported by the Russian Foundation for Basic Research under the projects 09-02-01084 and 09-08-01114 and by the Russian Ministry for Science and Education under the project 2.1.1/473.

P-66. Effect of magnetic field on ablatively driven Richtmyer - Meshkov instability induced by interfacial nonlinear structure Labakanta Mandal. R.Banerjee, S.Roy, M.Khan and M.R.Gupta Dept. of Instrumentation Science & Centre for Plasma Studies Jadavpur University,Kolkata,India e-mail: [email protected]

In an Inertial Confinement Fusion (ICF) situation, laser driven ablation front of an imploding capsule is subjected to the fluid instabilities like Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM) and Kelvin-Helmholtz (KH) instability. In this case dense core is compressed and accelerated by low densityablating plasma. During this process laser driven shocks interact the interface and hence it becomes unstable due to the formation of nonlinear structure like bubble and spike. The nonlinear structure is called bubble if the lighter fluid pushes inside the heavier fluid and spike, if opposite takes place. R-M instability causes non-uniform compression of ICF fuel pellets and needs to be mitigated. Scientists and researchers are much more interested on RM instability both from theoretical and experimental points of view. In this article, we have presented the analytical expression for the growth rate and velocity for the nonlinear structures due to the effect of magnetic field of fluid using potential flow model [1]. The magnetic field is assumed to be parallel to the plane of two fluid interfaces. If the magnetic field is restricted only to either side of interface the R-M instability can be stabilized or

113 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary : Abstracts - posters destabilized depending on whether the magnetic pressure on the interface opposes the instability driving shock pressure or acts in the same direction. An interesting result is that if both the fluids are magnetized, interface as well as velocity of bubble and spike will show oscillating stabilization and R-M instability is mitigated. All analytical results are also supported by numerical results. Numerically it is seen that magnetic field above certain minimum value reduces the instability for compression the target in ICE Reference: [1] Goncharov PRL, 88, 134502, 2002

P-67. Laser induced ablatively driven interfacial nonlinear fluid instabilities in multilayer targets Manoranian Khan. M.R.Gupta, L.K.Mandal, S.Roy and R.Banerjee Department of Instrumentation Science Jadavpur University, Kolkata-700032 India

High power laser driven shock waves in condensed matter have important application for studying equation of state (EOS) and high pressure physics. This is an important phenomenon in fuel compression for Inertial Confinement Fusion (ICF) experiments where multilayer targets of differing shock impedance are interacted by laser induced shocks. The interface between the two fluid becomes unstable when driven by the impulsive force (Richtmyer-Meshkov) due to such a shock wave or a continuously acting force e.g., gravity (Rayleigh- Taylo). In the nonlinear stage, the fluid interface is found to develop structures having finger-like shapes. The structures resemble a bubble (spike) accordingly as a lighter (heavier) fluid pushes in a heavier (lighter) fluid. These effects need to be mitigated for efficient compression in ICF experiment. We have studied the effect of density variation on R-T and R-M instability on the temporal development of nonlinear two fluid interfacial structures like bubble and spike. It is shown that the velocity of bubble or spike decreases leading to stabilization if the density of the fluids leads to lowering of the Atwood number. The Atwood number A = —— ' 1 ^ Pa+Pb changes to A* = where /?* = pm 1- — m = \a,b\, assuming PQ > p}). Pa+Pb m It has been seen that the stabilization or destabilization (depending on the algebraic sign of the gradient) will be proportional to the pressure pQ at the interface [1]. The set of equation describing the dynamics of the bubbles and spikes in presence of fluid density variation are not analytically intergrable in closed form. All the results are derived by numerical methods and are represented and interpreted. Analytical calculations are performed (not presented here) to modify the dynamical boundary condition between the two fluids and we have finally arrived at the following expression for the asymptotic bubble velocity V.2 = + I ^f"0 ^ ^ KL)\ where = b K 3r* 3i(ra-I)(rb-1) ra PI k = Wave number, g = gravity factor. Here L denotes the density gradient inhomogeneity scale length and L>0 or <0 accordingly as density is increasing or decreasing while .\jCa0Cb0 is proportional to pQ and CC =

[Cfl0 = Ya Pa / Pa\ Clearly instability is reduced if the bracketed term is negative. The opposite occurs when it is positive. We have obtained the conditions for stabilization of the fluid instabilities for various conditions of density variations of heavier fluid and or lighter fluid. It is interesting to note that compression of lighter fluid and decompression of heavier fluid leads to stabilize the two fluid interfaces which is desirable for ICF target design.

114 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

Numerical calculations are performed for composite target material (Au-foam) as well as (SF6 -Air).Results obtained would be useful for target design in ICF and studying EOS of material. References [1] D.Livescu Phys. Fluids. 16, 118, (2004) [2] Goncharov PRL, 88, 134502, 2002.

P-68. Effect of viscosity and surface tension on the growth of Rayleigh-Taylor Instability and Richtmyer- Meshkov instability under nonlinear domain Rahul Baneriee. M. Khan, L. K. Mandal, S. Roy and M. R. Gupta Dept. of Instrumentation Science & Centre for Plasma Studies Jadavpur University, Kolkata-700032, India E-mail: [email protected]

The Rayleigh-Taylor(R-T) instability and Richtmyer-Meshkov(R-M) instability are well known problems in the formation of some astrophysical structures such as the supernova remnants in the Eagle and Crab nebula. A core collapse supernova is driven by an externally powerful shock, and strong shocks are the breeding ground of hydrodynamic instability such as Rayleigh-Taylor Instability or Richtmyer-Meshkov instability. These instabilities are also important issues in the design of targets for inertial confinement fusion (ICF). In an ICF target, a high density fluid is frequently accelerated by the pressure of a low density fluid and after ablation the density quickly decays. So, small ripples at such an interface will grow. Under potential flow model, the perturbed interface between heavier fluid and lighter fluid form bubble and spike like structures. The bubbles are in the form of columns of lighter fluid interleaved by falling spike of heavy fluid. In this paper, we like to presented the effect of viscosity and surface tension on Rayleigh-Taylor instability and Richtmyer- Meshkov instability under the non-linear Layzer's[l] approach and described the displacement curvature, growth and velocity of the tip of the bubble as well as spike. It is seen that, in absence of surface tension the lowering of the asymptotic velocity of the tip of the bubble which is formed when the lighter fluid penetrates into the denser fluid and thus encounters the viscous drag due to the denser fluid, which depends only on the denser fluids viscosity coefficient. On the other hand the asymptotic velocity of the tip of the spike formed as the denser fluid penetrates into the lighter fluid is reduced by an amount which depends only on the viscosity coefficient of the lighter fluid and the spike is resisted by the viscous drag due to the lighter fluid. However, in presence of surface tension the asymptotic velocity of the tip of the bubble (spike) and nonlinear perturbed surface are oscillating under certain conditions. For Rayleigh-Taylor Instability this oscillation depends only on the surface tension but for Richtmyer-Meshkov instability it depends on surface tension as well as viscosity. References [1] D. Layzer, Astrophys. J., 122, 1 (1955).

115 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-69. Internal structures of laser generated plasma plumes N. Gambino1,3, D. Mascali1'2, S. Tudisco^, A. Anzalone1, A. Bonanno5, S. Gammino1, R. Grasso3, D. Leanza1, F. Musumeci1'3, L. Neri1'4, S. Privitera1'3, A. Spitaleri1'2 'INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania, Italy 2 Centro Siciliano di Fisica Nucleare e Struttura della Materia, Viale A. Doria 6, 95125 Catania, Italy 3 Universita degli Studi di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l'lngegneria, Viale A. Doria 6, 95125 Catania, Italy 4 Universita degli Studi di Catania, Dipartimento di Fisica e Astronomia Via S. Sofia 64, 95123 Catania, Italy 5INAF- Osservatorio Astrofisico di Catania Via S. Sofia 78, 95123 Catania, Italy

Fast expanding plasma plumes can be generated through the interaction of laser beams with metallic targets, at intensities above 109 W/cm2. The interest of scientific community in this field is constantly growing, because these plasma can be employed, for example, as tools for astrophysics studies, that are the subject of our investigation [1, 2]; on this purpose we measured properties of an Al plasma produced with a ND:YAG laser (1064 nm, 600 mj, 6 ns FWHM, power intensity up to 1012 W/cm2) installed at DMFCI of Catania by means of a Faraday Cup and a Langmuir Probe; the Langmuir probe was located close to the target (but at different distances, in the range 0.5cm- 12cm) and served as TOF and plasma resistive curve measurement device, in order to give plasma density and temperature versus the time through the analysis of the I-V current-voltage curve. The experimental data were then compared with hydrodynamical calculations [3,4]. Measured data reveal the existence of some inner plasma layers in which the Debye quasi-neutrality is violated because of internal self-generated electric fields: therefore the plume structure can be interpreted as ion multi-shells following fast electron layers. The quasi-neutral plasma core comes later, with a much lower expansion velocity. The evolution of expansion dynamics of each layer has been determined through the data and numerical calculations. A qualitative explanation of their formation is also given [5], based on instabilities due to the non-maxwellian nature of the expanding plasma. Evolution of the inner plasma structures at different background pressures is finally discussed. References [1] D. Mascali et al, Rad. Eff. & Def. in Solids, 165 (2010) 1-7. [2] S. Ivanovski et al, Rad. Eff. & Def. in Solids, 165 (2010). [3] S. Anisimov et al, Phys. Rev. B, 1993, 98 [4] N. Gambino et al, Rad. Eff. & Def. in Solids, 165, 6, 2010. [5] N. M. Bulgakova et al, Phys. Rev. E, 62, 2002,4.

P-70. Interaction of nanosecond EUV pulses with organic polymers H. Fiedorowicz, A. Bartnik, K. Jach, R. Jarocki, J. Kostecki, M. Szczurek, R. Swierczyriski, P. Wachulak Institute of Optoelectronics, Military University of Technology, Warsaw, 00-908, Poland

Interaction of nanosecond pulses of extreme ultraviolet (EUV) with organic polymers have been studied. The EUV pulses were produced from a compact laser plasma EUV source based on a gas puff target formed by pulsed injection of a small amount of gas under high-pressure into a laser focus region. The use of the gas puff target instead of a solid target allows for efficient generation of EUV radiation without debris production [1]. EUV radiation in the wavelength range of about 5 to 50 nm was produced by irradiation of xenon or krypton gas puff target with a commercial Nd:YAG laser operating at 10 Hz and delivering 4 ns pulses of energy up to 0.8 J per pulse. The time duration of the EUV pulses was about 3ns. The source was equipped with a grazing incidence axisymmetrical ellipsoidal mirror to focus EUV radiation in the relatively broad spectral range with the strong maximum near 10 nm. The size of the focal spot is about 1.3 mm in diameter with the maximum fluence up to 70 mj/cm2 [2].

116 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

The experiments on interaction of the EUV pulses of various polymers have been performed. Modification of polymer surfaces was achieved, primarily due to direct photo-etching with EUV photons and formation of micro- and nanostructures onto the surface [3, 4], The mechanism of the interaction is similar to the UV laser ablation where energetic photons cause chemical bonds of the polymer chain to be broken. However, because of very low penetration depth of EUV radiation, the interaction region is limited to a very thin surface layer (<100nm). This makes it possible to avoid degradation of bulk material caused by deeply penetrating UV radiation. The results of the studies should be applicable in biomedical engineering [5]. In the case of EUV irradiation of PMMA at relatively low fluence characteristic nodules of the size 100-200nm in diameter were observed on the surface [6]. It was suggested that dry desorption of polymer fragments which can be trapped several nanometers under the surface may form bubbles of nanometer size that lead to the nodule formation. The phenomenon is somewhat similar to the formation of nanovoids in silica in result of interaction of low-energy femtosecond laser pulses [7]. Computer simulation performed using the hydrodynamic code have shown that simultaneous absorption of few EUV photons in PMMA can lead to formation of the nodules. Acknowledgements. The research was supported by the Ministry of Science and Higher Education under the EUREKA project E! 3892 ModPolEUV, and the EC's 7. Framework Program (LASERLAB-EUROPE, ELI-PP and COST Action MP0601). References [1] H. Fiedorowicz, A. Bartnik, H. Daido, I.W. Choi, M. Suzuki, Optics Communications 184,161 (2000) [2] H. Fiedorowicz, A. Bartnik, R. Jarocki, J. Kostecki, L. Pina, M. Szczurek, P. Wachulak, Proc. of SPIE Vol. 7584 (2010) 75840U-1 [3] A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, A. Szczurek, M. Szczurek, Applied Physics B 96, 727 (2009) [4] A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, A. Szczurek, M. Szczurek, Acta Physica Polonica A 117, 384(2010) [5] B. Reisinger, M. Fahrner, I. Frischauf, S. Yakunin, V. Svorcik, P. Sajdl, H. Fiedorowicz, A. Bartnik, C. Romanin, J. Heitz, Applied Physics A (2010) - submitted [6] A. Bartnik, H. Fiedorowicz, R. Jarocki, J. Kostecki, M. Szczurek, Applied Physics B 98, 61 (2010) [7] S. Juodkazis, K. Misawa, T. Hashimoto, E. G.Gamaly, B. Luther-Davis, Appl. Phys. Lett. 88, 201909 (2006)

P-71. The effect of relativistic self-focusing and ramp density profile on the Plasma Wakefield Accelerators (PWFA) Mahdi Habibi1 'Islamic Azad University,Shirvan, Iran

An important aspect Plasma Wakefield Accelerators (PWFA) is stable propagation of the drive beam. In this paper, we have shown how an appropriate density ramp [1] at the underdense plasmas can be useful for achieving a matched beam. The results of a computational study of the drive beam interaction with electron density profiles are presented. When an optical beam transverses the nonlinear medium, the focusing distance becomes time-dependent as well as radially dependent. These works were performed with realistic difference densities and beam parameters. Nonlinear interaction processes have been considered. Preformed under dense plasma has been found to bottleneck fast electrons due to the intense magnetic fields generated near the critical surface. These results are in good agreement with the experiments and have demonstrated that the modeling of relativistic self-focusing of the drive beam. References [1] Sadighi - Bonabi,R„ et al. Phys. Plasmas, Vol. 16, No. 8. (2009), 083105

117 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-72. Dose dependent damage on fused silica based on micro crack formation due to single and multiple laser shots P.Parvin and M.Keraji Physics Dept, Amirkabir University of Technology, P.O.BOX 15875-4413, Tehran, Iran Corresponding author: [email protected]. ir

The purpose of this work is to understand the damage of the target irradiating a single intense pulse comparing a number of low power shots giving the same dose. Q-switched Nd:YAG laser ranging 10-1000 mj/pulse are used to irradiate the samples. The single laser shot with peak power of 100 j/cm2 generates an irreversible photodisruption on fused silica. The corresponding damage is reproduced by a number of multiple laser pulses exhibiting the same dose having smaller energy density of 1 j/cm2. The induced micro cracks appear within the solid after each laser shot connecting to each other due to the multiple shots to create an accumulative treeing effect. It is shown that the micro crack volume nonlinearly increases in terms of incident laser dose leading to an irreversible damage. Conversely, a single intense pulse induces a strong plasma formation associated with the Shockwave generation and the subsequent disintegration. The stylus profilometer were employed to investigate the surface damage and the volumetric crack formation were studied using dye penetration technique.

P-73.

A spectroscopic approach for analyzing the laser drilling of LiNbOa M. Stafe, C. Negutu, M. Mihailescu, S. S. Ciobanu, N.N. Puscas University 'Politehnica' of Bucharest, Physics Department, Spl. Independents 313, 060042 Bucharest, Romania

We present here an experimental investigation of the ablation-plasmas and of the craters generated by focusing visible nanosecond laser pulses at normal incidence, in atmospheric air, on a solid target of Er3+ doped

Ti:LiNb03 which has a relevant role in optoelectronics and photonics [1-4]. We analyzed the dependence of the craters dimensions and quality on the laser fluence. The fluence was varied between 1 and 1000 J/cm2 by changing the laser energy. The results indicate that the ablated volume increases linearly with fluence, whereas the ablation rate and crater diameter increase linearly with the square root of the fluence. The dimensions (depth and diameter) and the quality (thermal affected zone and the redeposit around the ablated structure) of the craters were further addressed by ablationplasma spectrometry during multi-pulse irradiation of the LiNb03 target. We analysed the relative intensities of the 611 and 671 nm Lil lines of the plasmas produced at different depths within the ablated structures as a function of laser fluence. We found a direct connection between the lines intensities and the dimensions and quality of the craters. Thereby, the ablation plasma spectrometry gives a way for estimating in real time the properties of the laser drilled holes.

Acknowledgements: This paper is supported by the Sectoral Operational Programme Human Resources Development (SOPHRD), financed from the European Social Fund and by the Romanian Government under the contract number POSDRU/89/1.5/S/64109 References: [1] L. Gui, H. Hu, M. Garcia-Granda, W. Sohler, G. Berth, A. Zrenner, Proc. 14 th European Conference on Integrated Optics (ECIO'08), Eindhoven, Netherlands, p. 71-74, (2008) [2] J. Lamela et al, Appl. Surf. Sci. 255, 3918-3922, (2009) [3] Mihai Stafe et al, 2009 Proceedings of SPIE 7426, art. no. 742614 [4] M. Stafe, I. Vladoiu, C. Negutu and I.M. Popescu, ICALEO Conf. Proc., (2008) P130

118 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-74. Conversion of Nd-glass laser multimode radiation into the second harmonic M.V.Osipov, V.G. Dmitriev, V.N.Puzyrev, A.T.Sahakyan, A.N.Starodub, B.L.Vasin P.N.Lebedev Physical Institue of RAS, Moscow, Russia

The second harmonic of high-energy Nd-glass laser radiation generated in a nonlinear KDP crystal has been studied theoretically for the case of fundamental radiation of the multimode laser of the "Kanal-2" facility, for which the experimental results on the conversion efficiency versus the power density, and the synchronism curves have been obtained. The following parameters of the fundamental radiation and typical features of the crystals have been used in the calculations: the wavelength - A = 1.06 pm, the radiation divergence -

P-75. Measurements of the laser induced plasma parameters for the identification of various metal targets P. Parvin1, B. Sajad2, S. Z. Shoursheini2 'Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran 2Physics Department, Alzahra University, Postal Code 1993891176, Tehran, Iran

We have shown that the laser induced plasma parameters such as the electron density (Ne) and temperature (T) are the unique properties for a definite metal targets, while the power density is kept constant during exposure. In this work, a Q-switched Nd:YAG laser (40 mj/pulse, 10 ns duration, 1 mm2focal area, 1 Hz P.R.R) was employed to generate the micro plasma on the pure metal targets such as Au, Ag, and Cu at the atmospheric ambient conditions. The characteristic peaks of the plasma emissions are analyzed to determine the corresponding Ne and T based on Boltzmann equation and Stark broadening effect. For a typical gold sample, those parameters are measured to be 2 xl017Cm3 and 7400 °K respectively. It emphasize that that the thermal properties of the targets such as conductivity, melting and evaporating points as well as the metal ionization potentials denote to be the key parameters to explain the significant differences obtained by breakdown spectroscopy.

119 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters

P-76. Suppression of stimulated Raman scattering due to localization of electron plasma wave in laser beam filaments Prerana Sharma and R.P. Sharma Centre for Energy Studies, Indian Institute of Technology, New Delhi -110 016, India

The filamentation of the high power laser beam by taking off-axial contribution is investigated when ponderomotive nonlinearity is taken into account. The splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. It is observed that the weak electron plasma wave (EPW) propagating in the z direction is nonlinearly coupled in the modified filamentary regions of the laser beam. The semi- analytical solution of the nonlinear coupled EPW equation in the presence of laser beam filaments has been found and it is observed that the nonlinear coupling between these two waves leads to localization of the EPW. Stimulated Raman scattering (SRS) of this EPW is studied and back reflectivity has been calculated. Further, the localization of EPW affects the eigen frequency and damping of plasma wave. As a result of this, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the back reflectivity. For the typical laser beam and plasma parameters with wavelength (A=1064nm), power 16 2 flux (= 10 W cm ), and plasma density (n/ncr) = 0.2; the back reflectivity was found to be suppressed by a factor of around 20 %.

P-77. Time resolved Thomson scattering on inhomogeneous targets P. Sperling1, R. Thiele', M. Chen2'3, Th. Bornath^ R.R. Faustlin", C. Fortmann5'6, S.H. Glenzer6, W.-D. Kraeft', A. Pukhov , S. Toleikis , Th. Tschentscher , and R. Redmer Institutf'urPhysik, Universit"at Rostock, D-18051 Rostock, Germany Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 71-259, Berkeley CA 94720, USA Institutf 'ur Theoretische Physik I, Heinrich-Heine-Universit'at D'usseldorf, D-40225 D' usseldorf, Germany "OESY, Notkestrafie 85, D-22607 Hamburg, Germany Department of Physics and Astronomy, University of California Los Angeles, Los Angeles CA 90095, USA Law- rence Livermore National Laboratory, P.O. Box 808, L-399, Livermore CA 94551, USA and European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany

The introduction of brilliant free electron lasers enables new pump-probe experiments to characterize warm dense matter states. For instance, a short-pulse optical laser irradiates a target (liquid hydrogen) that is subsequently probed with brilliant soft X-ray radiation. The strongly inhomogeneous plasma prepared by the optical laser is characterized with particle-in-cell simulations. The interaction of the soft X-ray probe radiation for different time delays between pump and probe with the inhomogeneous plasma is also taken into account via radiative hydrodynamic simulations. We calculate the respective scattering spectrum based on the Born- Mermin approximation for the dynamic structure factor considering the full density and temperature dependent Thomson scattering cross section throughout the target. We can identify plasmon modes that are generated in different target regions and monitor their temporal evolution. Therefore, such pump-probe experiments are promising tools to measure not only the important plasma parameters density and temperature but also to gain valuable information about their time-dependent profile through the target. The method described here can be applied to various pump-probe scenarios by combining optical lasers, soft X-ray as well as X-ray sources.

120 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-78. Laser induced nutation and production of quantum superposition state R. Bordoloi1 and R. Bora2 1Physics Department, Tinsukia College, Tinsukia, Assam - 786125, India 2Physics Department, Namrup College, Parbatpur, Assam - 786623, India *E-mail: [email protected]

Interaction of matter with near resonant radiation field has been studied. Equations of motion for the interacting atomic/ molecular dipoles have been derived and solved using RWA and rotation coordinate transformation technique. One of the solutions indicates to the occurrence of a periodic time variation in the population difference (inversion) of the interacting medium. In the light of Felix Bloch's work on nuclear induction, we propose that this behaviour is caused by the optical nutation of the dipole moments of the interacting atoms/ molecules. As an extension of F. Bloch's work on nuclear induction to optical frequency, we have showed that the nutation of the dipole vectors of the interacting molecules cause a dephasing among their transition probabilities. In act this dephasing leads the system to an intermediate superposition state thereby rendering it irresponsive to any external perturbation. A fine example of such behaviour is laser induced Optogalvanic effect both in gases and liquids.

Figure 1: Laser induced dephasing of the transition probability (inversion) and subsequent production of intermediate superposition state (the blue curve).

Acknowledgments: The authors acknowledge the help and guidance of Prof. G. D. Baruah, Retired professor and Head, Physics dept, Dibrugarh University, Assam, India. References [1] Allen and J.H.Eberly, Optical Resonance and Two Level Atoms. (John Willey & Sons. N-Y, 1975), p.no.132. [2] H. Goldstein, Classical Mechanics, (Narosa Publishing House, New Delhi 1989) [3] I.I. Rabi, Phys. Rev.51, 652(1937). [4] F. Bloch, Phys. Rev. 70, 460(1946).

121 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-79. The ablation rate measurements of metal targets in laser marking using double beam irradiation

including Q-SW Nd:YAG and CW-C02 laser S. Z. Shoursheini1. P. Parvin2, B. Sajad' 'Physics Department, Alzahra University, Postal Code 1993891176, Tehran, Iran 2Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran

Several experiments were performed to enhance the ablation rate on the gold samples, using simultaneous exposure due to a 100 W CW-C02 laser and a Q-switched Nd:YAG laser (40 mj/pulse, 10 ns, 20 Hz) having 2 similar focal areas (0.2 mm ). At first, C02 laser thermally increases the bulk temperature up to 800 °C before the application of Nd:YAG laser shots to preheat the surface. This changes the thermal and optical properties of the target leading to a greater energy coupling. In fact, there is a significant addition of sensible energy to the system which does not have to be supplied by the pulsed laser to heat plasma. Moreover, during the pulsed laser exposure, the inverse Bremsstrahlung contributes to reheat plasma due to the strong absorption cross section at the longer wavelength (10.6 pm), as a subsidiary effect. It significantly enhances the ablation rate respect to the single beam irradiation.

P-80. Interaction of two Cu plasma jets produced successively from the cylindrically shaped massive target A. Kasperczuk1, T. Pisarczyk1, J. Badziak1, S. Borodziuk', T. Chodukowski1, P. Parys1, J. Ullschmied2, E. Krousky3, K. Masek3, M. PfeiferJK Rohlena3, J. Skala3 and P. Pisarczyk4 'Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw, Poland 2Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, 182 00 Prague 8, Czech Republic institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Prague 8, Czech Republic 4 Warsaw University of Technology, ICS, 15/19 Nowowiejska St., 00-665 Warsaw, Poland

Our earlier papers demonstrate a very simple method of plasma jet formation, consisting in irradiating a massive planar target of a relatively high atomic number by a partly defocused laser beam. Our present interest is concentrated on interaction of the plasma jet with other media. This paper is aimed at investigations of interaction of two jets launched successively on Cu target. Our attention was paid to the role of radiative cooling in the plasma jet formation. The experiment was carried out at the PALS iodine laser facility. The laser provided a 250-ps (FWHM) pulse with energy of 130 J at the third harmonic frequency (X3 =0.438 pm). Two successive jets were produced on a massive flat Cu target provided with a cylindrical channel 5 mm long and 400 pm in diameter. Since the focal spot diameter of the laser beam on the target surface was larger than that of the channel (800 pm), the annular irradiation of the target face resulted in creation of the first plasma jet, whereas the second jet was produced by action of the central part of laser beam on the channel wall. Three- frame interferometric system, x-ray streak camera, and a set of ion collectors were used as diagnostic tools.

122 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-81. X-ray Thomson scattering in strongly correlated plasmas Th. Bornath1, T. Doppner2, C. Fortmann2, S.H. Glenzer2, G. Gregori3'4, B. Hoist1, W.-D. Kraeft1, H.J. Lee5, V. Schwarz1, P. Sperling1, R. Thiele1, R. Redmer1 'Institut fur Physik, Universitdt Rostock, 18051 Rostock, Germany 2Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551, USA 3Clarendon Laboratory, University of Oxford, Parks Road, Oxford 0X1 3PU, UK 4 Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Didcot 0X11 OQX, UK 5 LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA

With the advent of intense, coherent light sources in the XUV and soft X-ray regime, X-ray Thomson scattering (XRTS) becomes a versatile tool for the diagnostics of dense plasmas [1], X-ray pump-probe experiments were successful in spectrally resolving the non-collective (particle) scattering characteristics, and important plasma parameters such as electron density and temperature could be inferred. Recently, also the collective scattering feature (plasmons) has been probed. We present a systematic approach to the dynamical structure factor of dense plasmas which determines the XRTS spectrum using the Born-Mermin ansatz to include collisions via the dynamical collision frequency [2], Furthermore, ultra-fast XRTS has shown its capacity to temporally resolve the compression and heating processes in matter exposed to strong shock waves. The description of XRTS experiments in partially ionized systems is done based on the Chihara formula [3] assuming that free and bound electrons contribute to the X-ray scattering on an equal footing via the dynamic structure factor. The quasi-elastic ion feature is essentially determined by the dynamical ion-ion structure factor. The dynamics of the ion-ion structure cannot be resolved due to the comparatively large bandwidth of the probe radiation used in current XRTS experiments on dense plasmas. Therefore, it is appropriate to calculate the static ion-ion structure factor. We calculate the static structure factor of dense multi-component plasmas [4]. Large scale finite temperature density functional theory molecular dynamics (FT-DFT-MD) simulations are performed in order to cover the region where a consistent quantum treatment for the electrons is inevitable. Especially, the behavior at small wave numbers k can be inferred from the relation to the isothermal compressibility. Alternatively, the static structure factor is obtained by solving the integral equations for the pair correlation functions within the hypernetted chain (HNC) scheme. For this purpose we derive new effective two-particle quantum potentials for the interactions between the charge carriers from the full two-particle Slater sum by accounting for bound states. Comparison to the ab initio FT-DFT-MD simulations enables us to determine the short-range behavior of the effective electron-ion quantum potentials. Results for the static structure factor are presented for beryllium plasmas at given prototypical experimental parameters [1] at solid density and at threefold compression. Acknowledgements This work was supported by the Deutsche Forschungsgemeinschaft via SFB 652 and the BMBF via FSP-301 FLASH. References [1] S. Glenzer and R. Redmer, Rev. Mod. Phys., 81 (2009) 1625-1663. ' [2] A. Holl et al., High Energy Dens. Phys. 3 (2007) 120-130. [3] J. Chihara, J. Phys. Condens. Matter 12 (2000) 231-247. [4] V. Schwarz, et al., High Energy Density Phys. (2009), doi:10.1016/j.hedp.2009.11.005, in press.

123 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-82. Dense xenon nanoplasmas in intense laser fields P. Hilse1, Th. Bornath2. M. Moll1, M. Schlanges1 ' Institutfur Physik, E.-M.-Arndt-Universitat Greifswald, 17489 Greifswald, Germany 2 Institutfur Physik, Universitat Rostock, 18051 Rostock, Germany

One reason for the on-going interest in laser-cluster interactions is the efficient absorption of the radiation energy of near-infrared femtosecond laser pulses by clusters. Consequently, in laser-cluster experiments the emission of highly charged ions, very energetic electrons, higher harmonics, fast fragments as well as strong x-rays in the multi-keV range is observed. The cluster response is highly nonlinear. Different theoretical models and simulations indicate that resonant collective absorption plays a central role. The rapid expansion of irradiated clusters is essential as, at a certain time, the cluster reaches the density fulfilling the resonance condition. This can occur during a single pulse. A better control can be achieved by dual-pulse laser excitation with varying time delay between two pulses. A further optimization is possible by pulse shaping which is a modern tool in laser experiments. With pulse shaping, the dynamics of the system determined by heating, ionization and expansion can be specifically affected. For an understanding of the underlying physical processes in the dynamics of laser-cluster interaction, a theoretical description is presented using a genetic algorithm and basing on the relatively simple nanoplasma model [1]. Recently, experiments as well as calculations were performed for silver clusters [2]. Highly charged silver ions could be produced very efficiently with a pulse structure consisting of a smaller pre-pulse followed by a larger main pulse. The focus of the present contribution is on xenon clusters and their different behavior compared to metallic clusters as silver [3], Acknowledgements This work was supported by the Deutsche Forschungsgemeinschaft via SFB 652. References [1] P. Hilse, M Moll., M. Schlanges, Th. Bornath, Laser Physics 19 (2009) 428. [2] N.X Truong, P. Hilse, S. Gode, A. Przystawik, T. Doppner, Th Fennel, Th Bornath, J. Tiggesbaumker, M. Schlanges, G. Gerber, K.-H. Meiwes-Broer, Phys. Rev. A 81 (2010) 013201. [3] P. Hilse, Th Bornath., M. Moll, M Schlanges., Contrib. Plasma Phys. 49 (2009) 692.

P-83. Evolution of plasma emission on second harmonic frequency of Nd-glass laser radiation V.N.Puzyrev. A.A.Fronya, M.V.Osipov, A.T.Sahakyan, A.N.Starodub, B.L.Vasin, O.F.Yakushev P.N.Lebedev Physical Institute ofRAS, Moscow, Russia

The results of investigation of the second harmonic emission by the laser-produced plasma at laser radiation interaction with targets of different types are reported. The experiments have been carried out on the "Kanal 2" laser facility (a Nd-glass laser operating in a multi-mode regime, wavelength of radiation 1.06 pm, spectral width, 26k, power density on a target, 1013 W/cm2, focusing spot diameter, 350 pm.). The used targets are made 3 of Al, Cu, (C2H4)n, and TAC materials of 50 + 500 pm thickness and 2 + 8900 g/cm specific density, as well as the TAC+ Cu and Cu+Al two-layer targets have been used. Time sweep of the second harmonic generated in plasma (Fig. 1) has shown that the second-harmonic spectrum is broadened during a laser pulse. This makes it possible to believe that the turbulence developed in the laser- produced plasma due to the excitation of the short-wave plasma waves.

124 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary Abstracts - posters 3

• J \ 7,5 A wkjJih « %

V 12 A

42.3S ••-J—.''-* 15 A I Wvv y My lA-wV 0' i 2 3 4 3 6 t, ns r time averaged j \ / 5" V J 0" i 3 4

Fig.l. Spectral-temporal pattern of the second harmonic of heating laser radiation produced in a plasma. A - temporal sweep of the second harmonic; a), b), and c) -profiles of the radiation intensity in relative units in respect of the wavelength at different instants of the heating radiation; d) - averaged profile of the radiation intensity in relative units in respect of the wavelength during an action of the heating radiation; e) andf) -temporal scanning of the second harmonic and the heating radiation, respectively.

Acknowledgements This work is partially supported by the Russian Foundation for Basic Researches (grants ## 07-02-01148, 07- 02-01407, 10-02-00113), Program of the RAS "Nonlinear optical methods and materials for new generation of laser systems" and the Federal Target Program "Research and scientific-pedagogical cadres of innovative Russia" (grant # 2009-1.1-122-052-025).

P-84. Comparison between carbon nanostructures generated in water by ArF excimer laser and Q-switched Nd:YAG laser S.Z.Mortazavi \ P.Parvin '•*, A.Reyhani2, A.Nozad Golikand2, S.Mirershadi2 ' Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Iran 2 Material Research School, P.O.Box: 14395-836, Tehran, Iran

The laser ablation technique has been widely used for nanostructural processing because of its many advantages, such as easy transferring of target material composition into products at a low working temperature for high- melting and multicomponent materials. Liquid Phase Pulsed Laser Ablation (LP-PLA), in which a solid target is immersed in a liquid medium and the laser beam is focused through the liquid onto the target surface, was first reported by Patil and co-workers in 1987 [1-3]. For comparison purpose, in this investigation, ArF excimer laser at 193 nm and Q-switched NdrYAG laser at 1064 nm were focused on the graphite target immersed in the water for carbon nanostructures generation. The results show that the UV and IR wavelengths strongly affect on the morphology and structure of the generated nanoparticle. The interaction of the laser with the target causes the surface to vaporize as an ablation plume. It contains species such as atoms, ions, and clusters, travelling

31st ECLIM • 6-10 September, 2010 - Budapest, Hungary 125 c Abstracts - posters )

fast having high kinetic energies. The inverse bremsstrahlung (IB) absorption in the plum of plasma can explain this wavelength dependent process [4], X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and Raman spectroscopy were performed to characterize structure and morphology. The carbon nanostructures generated by the Nd:YAG laser contain graphite and fullerene but the ArF excimer laser produces nanodiamond. The TEM micrographs showed that the nanostructures generated by Nd:YAG laser are similar to porous nanocluster and notably larger than those of ArF laser.

Fig. I. TEM images of carbon nanoparticles generated by a) Nd:YAG and b) ArF excimer laser

References [1] Patil P P, Phase D M, Kulkarni S A, Ghaisas S V, Kulkarni S K, Kanetkar S M, Ogale S B, Bhide V G, Phys. Rev. Lett., 1987, 58, 238. [2] Yang G W, Wang J B, Appl. Phys. A, 2000,71, 343. [3] Wang J B, Zhang C Y, Zhong X L, Yang G W, Chem. Phys. Lett., 2002, 361, 86. [4] Shalom Eliezer: The interaction of high-power lasers with plasmas, Institute of Physics, London (2002).

P-85. Femtosecond laser produced high intensity X-ray source for the pin-point treatment of cancers N. Kawashima1, H. Muramatsu2, C. Yanagimoto2, M. Miyazawa3 and E. Kajiwara3 ' Liaison Center, Kinki Univ, 3-4-1 Kowakae, Higashi-Osaka City, Japan 577-8502 2LaserckInc, 9-84-1, Minamikinomoto, Yao-shi,Osaka Japan 3 School of Medicine, Kinki Univ, 377-2 Ono-Higashi, Osaka-Sayama City, Japan 589-8511

In order to overcome the problem that the cancer treatment using the X-ray radiation is a powerful tool, however, it kills not only diseased organs but also healthy ones, we have developed a localized X-ray source by using a Femt-second, which enables a pin-point treatment of cancers. A Femt-second laser system of IFRITE (Cyber Laser Inc.) is used. It has the following characteristics: Pulse width: 200 fs; Energy/pulse: lmj/pulse; Repetition: 1 kHz. The laser is focused on a special tape and a strong X-rays are obtained in the direction of the laser beam (behind the tape). The peak energy of the obtained X-ray is about 12 keV, having a long high energy tail. 15 min irradiation dose is about lOOGy. For the test of X-ray irradiation on the cells of FBL3, mouse tumor cell are used and the DAPI staining test shows that most of the cells have been killed. We have also done the DNA laddering test and as shown in the attached photo, the DNA laddering structure is clearly seen.

126 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

The initial test of an irradiation on a FBL3 tumor planted on mice shows an appreciable effect to suppress the growth of the tumor. We have confirmed that to develop a system to install the X-ray source in 15 mm pipe for a practical use for the pin-point irradiation on human cancers is possible.

Maker No X-ray X-ray 20min

2000b^

500b^

Acknowledgements This work is supported by the MEXT Collaboration Project with Lacal Communities Medi-Techno Collaboration (2006 - 2011).

P-86. Engineering nanostructures for MHz XUV light sources Y.-Y. Yang1-", S.L. Stebbings1, F. SuBmann1, M. Durach4, D. Lehr5, W. Schneider1,I/Pupeza16, J. Raster1'6, O. Pronin16, Z.-S. Zhao^X.-M. Duan2, M.I. Stockman4, E.-B. Kley5, E. Fill16, F. Krausz16, M.F. Kling1 1 Max Planck Institute of Quantum Optics, Garching, Germany 2 Technical Institute of Physics and Chemistry, CAS, Beijing, China 3 Graduate School of CAS, Beijing, China 4 Department of Physics and Astronomy, Georgia State University, Atlanta, USA 5 Institute of Applied Physics, Friedrich Schiller University of Jena, Jena, Germany 6 Department of Physics, LMU, Garching, Germany

A well-established technique for the production of attosecond extreme-ultraviolet (XUV) light pulses is high harmonic generation (HHG)111 in noble gases. XUV light generation at MHz repetition rates, which enable highly time-resolved spetroscopies, is a challenging task due to the high intensities required for this nonlinear process. Two approaches are followed in our work, both incorporating the design of tailored photonic nanomaterials. The first approach is based on the seminal work by Kim et al '2|. This technique exploits the plasmonic field enhancement in coupled nanostructures for the generation of XUV light using relatively low incident laser intensities. We have theoretically studied the influence of the sub-cycle field evolution of the driving laser field on the generated plasmonic fields in a variety of isolated and coupled nanostructures. This has allowed us to identify feasible conditions for the generation of single attosecond pulses. The second approach utilizes an external, stabilized enhancement cavity[3) to achieve sufficient intensities while maintaining the MHz repetition rates. XUV light is generated from an intra-cavity gas jet and subsequently extracted from the cavity with an optimized output coupler. We have theoretically studied the design of nano-

127 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters 3 periodical gratings 141 which can serve as diffractive elements for the harmonics (Fig.l), enabling their output- coupling and energy selection.

-Outcoupled Power (nW) -Coupling Efficiency (Ref. 4) -Coupling Efficiency (Optimimum)

Harmonic Order

Figl. The efficiency calculated in ref. 4 is compared with the efficiency of a grating optimized in the present work. Optimization parameters include groove depth, groove period and aspect ratio. The dip in efficiency at 71 nm (Harmonic order: 15th) is due to the fact that the refractive index of Si02 at this wavelength is close to one.

References [1] P. B. Corkum, Phys. Rev. Lett. 71, 1994 (1993). [2] S. Kim et al., Nature 453 ,757 (2008). [3] I. Pupeza et al.,Opt. Lett. 35, 2052 (2010). [4] D. C. Yost et al., Opt. Lett. 33,1099 (2008).

P-87. The 3D computer simulation of 200 MeV proton beam generation at the interaction of PW-laser radiation with low-density targets D. V. Torshin1 and V. A. Lykov1 'Russian Federal Nuclear Center - VNIITF: Vasilyeva str. 13, Snezhinsk, Chelyabinsk reg., 456770, Russia

Laser ion acceleration attracts significant attention because of their possible applications in medicine, science and technologies. The low-density targets (gas jets or low-density foam) have a great interest because they do not produce special requirements to contrast of the laser pulse and they are suitable for operation at high repetition rate. There are experiments on laser ion acceleration with low-density targets [1,2] and the 2D calculations were performed with using PIC-codes [1-3], In this report we presents results of 3D calculation performed by Mandor code [4] for searching optimal condition of the generation protons with energy about 200-250 MeV at high intensity laser irradiation of low- density jets and aerogels. The 3D calculations proved feasibility of proton acceleration to therapeutic energies from hydrogen jets of density (2-3)-ncr and thickness of 18 pm that irradiated by laser pulses of duration 10-30 fs, peak power about (1-2) PW and intensity up to 1022 W/cm2.

128 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

. • ' 109 ? 1°8

w

* 7 3 10 ~55

I 106 ITTT^- Q_ 2 -- |1 105 V

0 100 200 300 400 500 600 Figure 1. Calculated proton spectra obtained for PW laser light irradiation of 18 fim targets with initial electron

concentration 4 ncr. 1 - the 2D calculation for hydrogen target, 2 - the 3D calculation for hydrogen target, 3 - the 3D

calculation for CH2 target.

3D Mandor calculations have demonstrated possibility of proton acceleration to therapeutical energies from low-density organic foams. However the maximum energy of protons accelerated from the CH2-foam target reduced by about 20% compared with the hydrogen target and the number of protons accelerated to energies near 200 MeV is reduced by ~ 2 times. Our calculations and estimations suggest that these losses could be compensated if increase the laser intensity at low-density foam by a factor of about 2 and use targets with the maximum concentration of hydrogen. Acknowledments. The authors would like to thank D. V.Romanov for development Mandor code and advices, A.V.Brantov for useful discussion and S.Yu.Mokshin, E.M.Romanova for assistance during providing calculation. This work was supported by ISTC, grant No. 2289. References [1], L.Willingale.S. P. D. Mangles,P. M. Nilson, et al. Phys. Rev. Lett 96, 245002 (2006). [2], L.Willingale, S. R. Nagel, A. G. R. Thomas, et al. Phys. Rev. Lett 102,125002 (2009). [3], S. S. Bulanov, V. Yu. Bychenkov, V. Chvykov, et al Phys. Plasmas 17,043105 (2010). [4], D.V.Romanov et.al. PhysRevLett Vol 93, 21, 215004(2004).

P-88. Hydrodynamics computation of ion accelerated in interaction of laser with preformed plasma E.Yazdani1, H.Hora2, R.Sadighi-Bonabi2, H.Afarideh1 'Physics Department ofAmirkabir University of technology 2 Departments of Theoretical Physics, University of New South Wales, Sydney 2052, Australia 3 Physics Department of Sharif University of technology

Production of highly directed ion blocks by laser plasma interaction may provide one requirement to produce a fast ignition deuterium tritium fusion at densities not much higher than the solid state by a single shot PW-ps laser pulse. In this work, numerically we study that, in which condition the accelerated plasma blocks produced by nonlinear force may reach to the highest possible thickness. For doing this, we consider the effects of preplasma profiles with various target thickness as an initial conditions. Study of laser wavelength dependency on penetration depth in the target is also investigated. The characteristics of the results of computations are compared with the expected theoretical values that is confirmed the detailed inclusion of plasma dynamics in the computations.

129 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-89. Ultrashort pulse laser acceleration of protons T. Metzkes, K. Zeil, S. D. Kraft, M. Bussmann, T. E. Cowan, T.Kluge, U. Schramm Forschungszentrum Dresden - Rossendorf, Bautzener Landstrafie 400, 01328 Dresden, Germany [email protected], www.fzd.de/fwt

In the last years, high power laser systems in the 100 TW range with ultrashort pulses (-30 fs) and repetition rates of up to 10 Hz have come into operation. In order to investigate the laser proton acceleration in this laser regime we have performed a series of experiments using plain few-micron-thick metal targets and mass-limited silicon targets. The targets were irradiated with 30 fs pulses from the new 150 TW DRACO Laser facility at the Forschungszentrum Dresden-Rossendorf which show a contrast level of 10"10 in the picosecond and 10~9 up to 10"10 in the nanosecond range. For both target types, proton spectra have been measured with a magnetic spectrometer and radiochromic film stacks. In addition, two magnetic electron spectrometers at different angles have yielded information on the electrons emitted from the non-irradiated target rear side. Using plain metal foil targets, we have observed a linear scaling of the maximum proton energy with laser power and could show that this behaviour is explained consistently by Schreiber's analytical scaling model [1] in the limiting case of ultrashort laser pulses [2]. Despite the high laser contrast we have found that a slight deformation of the target rear side results in a predictable deflection of the emission of energetic protons away from the target normal direction [2]. The mass limited targets tested in the experiment were micromachined silicon foils with lateral sizes of 20x20 pm2 to 100x100 pm2 mounted on tiny stalks. Their thickness of 2 pm corresponded to the optimum target thickness for proton acceleration at DRACO. Depending on the size of the targets strong influences of the stalks as well as the target edges were found which could both increase or decrease the maximum proton energy in comparison to a plain foil. References [1] J. Schreiber et al., PRL 97,045005 (2006) [2] K. Zeil et al., N)P 12, 045015 (2010)

P-90. Improving the predicted potential and energy of the monoenergetic electrons in an alternative ellipsoid bubble model M. Fanaei, Sh. Rahmatallahpur, and R. Sadighi-Bonabi Department of Physics, Sharif University of Technology, 11365-9161, Tehran Iran

At the relativistic region, the maximum energy of electrons in the ellipsoid model is about 25% more than the spherical model, and this is confirmed by PIC and the measured experimental results reported here. The electron energy spectrum is also calculated, and it is found that the energy distribution ratio of electrons AE/E for the ellipsoid model in the here reported condition is much less that of the spherical model. This is in good agreement with the experimentally measured value in the same condition. In this regime, the parameters of the quasi-monoenergetic electrons output beam can be described more appropriately. In this work, intense femtosecond laser pulse was focused on the best matched point above He gas jet to obtain a stable ellipsoid bubble. The obtained monoenergetic electron energy spectrum is properly explained by the ellipsoid model introduced here. The presented ellipsoid cavity model is more consistent than the previous spherical model, and it explains the monoenergetic electron trajectory more accurately.

130 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-91. Calculation of X-ray emission produced by a quasi-monoenergetic electron distribution M. Fanaei1, L. Nikzad2, R. Sadighi-Bonabi*1 ' Department of Physics, Sharif University of Technology, Tehran, Iran; 2 School of Optics and Laser, Tehran, Iran; "corresponding author, R. Sadighi-Bonabi

By using an intense ultrafast laser interaction with plasma, generation of accelerated relativistic electrons with quasi monoenergetic spectrum has been possible. Analytic expressions for spectra and emission efficiencies of x-rays bremsstrahlung and characteristic line emission produced by a quasi-monoenergetic electron distribution from several targets are investigated. In this work, a Gaussian profile is assumed for the quasi- monoenergetic electron spectrum. The produced x-ray radiations are compared with the previous achieved results for a Maxwellian electron profile. These results and achievements are discussed in detail. Also, the outcomes can be evaluated with the experimental and simulated results.

P-92. New laser-driven nuclear excitation studies: concepts and proposals L. Drska, V. Hanus, M. Sinor Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, 115 19 Prague 1, Czech Republic

There has been a great interest in the processes of nuclear excitation and triggering in high-parameter laser- produced plasmas in recent years. A series of papers devoted to the theory of this event has been published. Several experiments have already been attempted to study the excitation of the lowest nuclear levels of medium / high-Z nuclides (Ta 181, U 235 etc.), all the same unsuccessful or inconclusive [1], [2]. In the first part of this paper, the situation will be overviewed and analysis of the reasons of this unsatisfactory state of affairs will be accomplished. Prospects of the possible solving of the problem by using novel / projected laser facilities (esp. LIL / PETAL, XFEL, ELI-Phasel) will be outlined. Potential of the future ELI Beam Facility in the Czech Republic [3] in this area will be stressed. In the second part, some proposals for the excitation and triggering studies using combined high-power and high-intensity LIL / PETAL system (2012) with multikilojoule and multi-petawatt parameters [4] will be discussed. Results of preliminary simulations supporting the thinking about potential projects will be shown and conditions essential for meaningful effort in this area will be analyzed. Problems of realistic simulations of such experiments will be addressed. Completely novel chances for the excitation / triggering studies would be started by constructed / projected facilities XFEL (coherent X-rays -12 keV, 2014) [5] and ELI (multi-petawatt Phase 1, 2015). Application of intense / coherent high-energy X-rays and / or intense electron / ion beams allows new experimental schemes, extends the range of nuclides to be studied and (maybe) will enable to test some new triggering methods. In the last part of the presentation some possibilities in point (esp. for ELI Beamlines), will be drawn up. Acknowledgements This research has been supported by the Research Program No. 6840770022 of the Ministry of Education, Youth and Sports of the Czech Republic. References [1] F. Gobet, F. Hannachi, M.-M. Aleonard et al., J. Phys. B : At. Mol. Opt. Phys. 41, 145701 (2008). [2] L. Drska, R. Liska, M. Sinor and P. Vachal, in Proc.of the XXX ECLIM, Darmstadt, Sept. 2008. Report TUD-2009, 75 (2009). http://www.gsi.de/forschung/pp/dates/ECLIM2008.html [3] B. Rus, in 24th Symp. on Plasma Physics and Technology, Prague, June 14 - 17, 2010. [4] S. Hulin, G. Thiell, D. Raffestin and N. Blanchot, Support to the definition of new diagnostics for the 2012 - 2014 LIL-PETAL facility. http://dev.petal.aquitaine.fr/IMG/pdf/Support LIL-PETAL 2012-2014.pdf [5] European XFEL, http://www.xfel.eu/

131 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-93. Laser magneto-cumulative accelerator of charged particles N. Vogel1. V.A. Skvortsov2 lUniversity of Technology Chemnitz, Department of Physics, 09107Chemnitz, Germany 2Moscow Institute for Physics and Technology (State University), 141700, Russia, Moscow region, Dolgoprudny, Institutive lane, 9

High energy ion generation (energy in order of lGev) have been estimated by interaction of picosecond laser pulses with an intensity of 6xl014 W/cm2 with metallic target in vacuum and gas atmosphere. In this paper we shall discuss the production of very high magnetic fields by flux compression in laser-induced plasmas and show experimental results on particle acceleration due to an explosively, collapsed magnetic fields. Different nuclear track detectors have been used for heavy charged particle registration and identification: mica, plastics (Cr-39), and glasses. Magnetic fields generated in laser-induced plasmas of order 35 MGauss have been estimated by means of Faraday rotation and interferometric diagnostics with high temporal and spatial resolution [1-3].

Fig.l Ta-ions tracks in etched mica. Fig.2 Ta-ions tracks in etched plastic nuclear detector CR-39 coved with 330 fjm Cu. References [1] Vogel N., Kochan N., "Experimental investigation of stochastic pulsation and formation of light bullets with megagauss magnetic fields by an intense laser pulse propagating in a preionized plasma", Phys. Rev. Lett., 86, (2001), 232-235 [2] N .Vogel, "Experimental Investigation of Megagauss Magnetic Fields in Self-focused Plasma Channels and Accelerated Plasma Blocks", in Inertial Fusion Science and Applications 2001, p. 266 (Ed.: K. A. Tanaka, D.D. Meyerhofer, J. Meyer-ter-Vehn), ELSEVIER, Paris, Amsterdam, New York, Oxford, Shannon, Tokyo, 2001. [3] N. Vogel,''Diagnostics of picosecond laser pulse absorption in preformed plasma", Applied Surface Science, 252, (13), (2006), 4850-4856.

P-94. Ultra-intense proton beams driven by laser-induced cavity pressure J. Badziak, S. Jabloriski, P. A. Raczka Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw, Poland

Proton-driven fast ignition of a fusion target requires collimated proton beams of relatively low mean proton 20 2 energies ( < lOMeV) but of extremely high intensities (Ip~10 W/cm ) and powers (Pp~ 1PW). In addition, the laser-to-proton beam energy conversion efficiency r| must be sufficiently high (r|>15%), in order to keep 2 20 2 2 the required laser driver energy below 100 kj. Unfortunately, at relatively low values of IL^ <10 Wcm pm ,

132 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters ) imposed by the constraint on (IL - the laser intensity, X - the laser wavelength), attaining the required conversion efficiency with the currently known techniques of laser-driven proton acceleration is difficult. Very recently, a novel highly efficient scheme of laser acceleration of dense matter called laser-induced cavity pressure acceleration (LICPA) has been proposed [1]. In this scheme, a target placed in a cavity is irradiated by a laser beam introduced into the cavity through a hole and accelerated along a guiding channel by thermal pressure created in the cavity by the laser-produced plasma or by the photon pressure of the laser radiation trapped in the cavity. Extremely high energetic efficiency of LICPA in the thermal pressure regime has been demonstrated in the experiment on the high-power PALS laser facility [1], In this contribution, the possibility of highly efficient generation of proton beams using LICPA in the photon pressure regime is investigated by means of particle-in-cell simulations. In the simulations, a 2co Nd:glass laser 2 20 2 2 beam of circular or linear polarization and ILA < 10 Wcm pm has been used as a proton driver. In particular, it is demonstrated that the circularly polarized laser driver can produce in the LICPA scheme ultraintense 21 2 (Ip~10 W/cm ) and dense proton bunches of a relatively narrow energy spectrum with conversion efficiency well above 20%. The effect of laser intensity, the target thickness and the cavity length on the proton beam parameters is examined. References [1] J. Badziak et al., Appl.Phys.Lett. 96, 251502 (2010).

P-95. Plasma effects in the high-intensity laser driven electron-positron production on a thin foil P. A. Raczka Institute of Plasma Physics and Laser Microfusion, 01-497 Warsaw, Poland

An intense laser pulse interacting with a thin foil produces separate bunches of high energy electrons and ions. At ultra-high intensities the energies of the accelerated particles are way above the threshold for the electron- positron pair production in the electron-ion collisions [1] The problem of laser induced pair production in the interaction with a foil received recently some attention [2], as there are hopes this might become a practical and prolific source of positrons. In this note we consider the problem of laser-induced positron production in a setting with a thin foil of low-Z material, as is often the case in the targets prepared primarily for the study of particle acceleration process. Our motivation is that the positron signal is an important complement of the electron and ion signals in the laser-foil interaction and therefore should be thoroughly studied. Additionally, the phase space distribution of the produced positrons could carry important information on the details of laser-plasma interaction within the target, shedding additional light on the fine details of the particle acceleration process. As a first step we consider the case of circularly polarized pulse, incident on a thin (1-50 pm) target of low Z fully ionized plasma. To estimate the positron production we solve numerically the equations of motion for collisionless plasma in one spatial dimension [3]. We assume for simplicity that initially the plasma is quiescent and take the advantage of the fact that translational energies of electrons and ions accelerated by the laser pulse are typically much larger than any thermal energies. We provide estimates which in principle could be verified in the laser acceleration experiments. References [1] J.W. Shearer et al., Phys. Rev. A 8,1582 (1973). [2] Hui Chen et al., Phys. Rev. Lett. 102, 105001 (2009). [3] P. Bertrand et al., Phys. Fluids B 2, 1028 (1990).

133 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary ) c Abstracts - posters

P-96. Electromagnetic fields of ultra short laser pulse propagations and density changes in the ramped density plasma R. Sadighi-Bonabi*, P. M. Ara, M. Moshkelgosha and H. A. Navid Department of Physics, Sharif University of Technology, 11365-9567, Tehran, Iran "'Corresponding author: e-mail: sadwhi&sharif.ir

By using Maxwell equations and the nonlinear dielectric permittivity, the electric and magnetic field profiles along with the achieved density profiles in plasma with and without the ramped density are investigated. It is found that the electromagnetic fields are deviated from its normal sinusoidal profile and the wavelength of electric and magnetic field oscillations increases in comparison to the uniform underdense plasma. The effect of the weakly relativistic ponderomotive force generated by intense laser pulses in the underdense plasma with initial density ramp and temperature variations is studied. It is noticed that ponderomotive force modifies the electron density distribution and the steepening of the plasma density increases in the presence of the electron density with ramp profile.

P-97. Cavity Pressure Acceleration - an efficient laser-based method of production of high-velocity macroparticles S. Borodziuk1, A. Kasperczuk1, T. Pisarczyk1, J. Badziak1, T. Chodukowski1, J. Ullschmied2, E. Krousky3, K. Masek3, M. Pfeifer3, K. Rohlena3, J. Skala3, and P. Pisarczyk4 'Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw, Poland 2Institute of Plasma Physics AS CR, v.v.i., Za Slovankou 3, 182 00 Prague 8, Czech Republic 3Institute of Physics AS CR, v.v.i., Na Slovance 2, 182 21 Prague 8, Czech Republic 4 Warsaw University of Technology, ICS, 15/19 Nowowiejska St., 00-665 Warsaw, Poland

A non-classic and very efficient method of macroparticles (foil fragments) acceleration is proposed. For this reason the "cavity" type targets were designed and tested. The pressure induced by laser action inside the target cavity constitutes here the most important factor of foil acceleration. Cavity pressure is able to accelerate macroparticles very efficiently in arbitrary direction. The reported experiment was carried out at the Prague Asterix Laser System. To study macroparticle velocity and efficiency of plasma energy transfer to accelerated foil a three-frame shadography technique was used. This mechanism of acceleration was named as a "Cavity Pressure Acceleration (CPA). Our results (high velocity of accelerated foil/macroparticle, possibility of accelerating heavy macroparticles) show that they can be applied to study impact fast ignition and impact fusion problems. This method (CPA) leads to significantly higher velocities of flyer foils than those obtained in traditional way (ablative acceleration scheme) in similar experimental conditions. Maximum velocity obtained for thin (10 pm Al) foil was close to the top results observed in ILE Osaka, where much more powerful laser system was used. It stems from the fact that CPA allows to use almost all of the absorbed laser energy (neglecting the energy of the shock wave propagating into the solid target). Also the hydrodynamic efficiency of the energy transfer to the flyer foil is much higher. Very high hydrodynamic efficiency obtained in CPA experiment may offer a chance to construct an impact ignitor for laser fusion experiments. Another advantage of CPA method is that there is no need (contrary to the case of laser ablative acceleration method) to apply shortwave lasers or to convert laser radiation to higher harmonics. Generally, for the moderate laser light intensities (I, ~ 1015 W/cm2) the results (velocity, hydrodynamic efficiency) obtained for the first harmonic are (at least) as good as those for the third harmonic of iodine laser, which was previously used in our experiment.

134 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

P-98. Pulsed laser deposition simulation for graphite target using Monte-Carlo Method Sh. Tarn, F. Izadi Shiraz University of Technology, Iran

Pulsed laser deposition method for producing thin films is investigated. This deposition method include several stages such as absorption of the laser beam in the target material, evaporation of the material producing plume of atoms or molecules, strong interaction of the laser beam with the plumb to produce plasmas, and finally deposition of atoms or molecules on the substrate surface. The growth of the thin film in the initial stage is simulated using Mont Carlo method. Our simulation indicated that by decreasing the duration of the pulse together with the decrease in laser energy, the thin film growth is steady so that the uniform and homogenous layer is produced.

P-99. Plasma mirror for cleaning KrF laser pulses Istvan B. Foldes1, Angela Barna1, Daniel Csati2 and Sandor Szatmari2 'KFKI Research Institute for Particle and Nuclear Physics, Association EURATOM HAS, H-1525 Budapest, Hungary 2 University of Szeged, Department of Experimental Physics, H-6720 Szeged, Dom ter 9. Hungary

Temporal contrast of ultrashort pulses is one of the most critical issues for high-intensity laser-plasma interactions. The higher the intensity, the larger contrast is needed for keeping prepulse levels low enough to avoid preplasmas which may modify in an undefined way the initial conditions for the interactions with ultrashort laser pulses. Recently plasma mirrors[l] became the ultimate tool for cleaning ultrashort laser pulses from pedestals in the visible/IR spectral range using solid-state laser systems. For UV lasers as KrF systems the plasma reflectivity is lower, therefore it was questionable whether plasma mirrors can be used for KrF systems as well. The short-pulse KrF system in our laboratory (70mJ/610fs) uses direct and not chirped-pulse amplification, therefore the pedestals originate solely from the ASE of the KrF amplifiers. Although - as a consequence of limited focusability and longer duration of the ASE - intensity contrast as high as 1010 can be obtained, it is still not sufficient in some cases. A prepulse with duration of 15ns with 107W/cm2 intensity may cause photoablation and ionization of the solid target, i.e. the main pulse does not hit a pure solid any more in case of 1018W/cm2 focused intensity. Plasma reflectivity was investigated using 45° and 12.4° angle of incidence. The antireflection-coated target was moved by stepping motors shot-by-shot. The energy was monitored for each shot and the reflected radiation was measured by calibrated photodiodes. The diode signal was integrated by a peak-hold detector and digitized, controlled by a microprocessor. Fiber-based communication provided the isolation from electronic noises. Plasma mirror effect was demonstrated for ultrashort KrF laser pulses. The reflectivity starts to increase above 1012W/cm2 and it reaches a maximum at ~1014W/cm2, above which it saturates and even decreases with large shot-to-shot variations due to the nonlinear phenomena (e.g. harmonics generation) above this intensity. The measured maximum reflectivity was found to be ~33% for 45°angle [2] of incidence, and it was nearly 50% for 12.4°. The obtainable 50% reflectivity allows its direct application for high-intensity experiments but new schemes are shown their possible application before the final amplifier using the saturation properties of the KrF amplifiers. References [1] H.Kapteyn, M. Murnane, A. Szoke, R. Falcone, Opt. Lett. 1991,16, 490-492. [2] I.B. Foldes, F.L. Szucs, D. Csati, S. Szatmari, Rad. Effects and Defects in Solids, 2010, in press

135 31st ECLIM • 6-10 September, 2010 - Budapest, Hungary c Abstracts - posters )

Acknowledments This work, supported by the European Communities under the contract of Association between EURATOM and the Hungarian Academy of Sciences, was carried out within the framework of the European Fusion Development Agreement. It was also supported by the Hungarian OTKA foundation Nr.60531 and by the IAEA CRP on Path- ways to Inertial Fusion - An Integrated Approach, Research Contract no. HUN13759.

P-100. Novel hollow fiber compressor for high power, multi-mj ultrafast lasers T. Nagv1. W. Schweinberger2, A. Sommer2, M. Schultze2, R. Kienberger2, F. Krausz2, P. Simon1 'Laser-Laboratorium Gottingen e.V., Hans-Adolf-Krebs-Weg 1, 37077Gottingen, Germany 2Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany

The current trends in ultrafast laser development include, besides the reduction of the pulse duration, also the up-scaling of the pulse energy and the increase of the repetition rate. Recently, multi-mj, multi-kHz lasers delivering sub-30 fs pulses have become available. The compression of the output pulses of such lasers to sub-5 fs duration is a challenging task In order to maintain good temporal contrast and beam profile, the preferred way for spectral broadening is to use noble-gas-filled hollow fibers. For launching multi-mj pulses in the waveguide, its inner diameter has to be large in-order to keep the intensity at low levels so that the ionization losses are still tolerable. For optimal in-coupling the differential pressure scheme1 is very favourable, which, however requires longer waveguide lengths to compensate for the reduced effective interaction length caused by the pressure gradient. Recently, a novel hollow fiber construction has been developed comprising a waveguide formed by a stretched flexible capillary tube2. This special construction resolves the usual strong limitation to the length of the waveguide, provides excellent straightness, and inherently supports the differential pressure scheme. The only drawback of the flexible fiber unit to date was its susceptibility to thermal damage in case of high average power input beams. To solve this problem we present a novel composite fiber unit, which consists of a thick-walled taper followed by a long flexible fiber. This construction combines the advantages of both types: the high resistibility of the taper and the free length-scalability of a flexible fiber. In order to demonstrate the potential of the new fiber design, a 2 m long composite fiber with an inner diameter of 320 pm was placed' at the output of a CPA Ti:Sa laser system comprising an oscillator, a grating-prism [grism] stretcher, two multi-pass amplifier stages and a compressor combining bulk glass blocks with chirped mirrors. The laser delivers 26 fs pulses with a pulse energy of 2mJ at a repetition rate of 4 kHz. The whole system can be CEP stabilized and the spectral amplitude and phase can be fully controlled by a programmable AOM which is implemented in the first multi-pass amplifier. Using a pressure gradient scheme with 1.7 bar Ne, a spectrum with -500 nm bandwidth has been recorded

Wavelength fnml References [1] A. Suda, M. Hatayama, K. Nagasaka, and K. Midorikawa, Appl. Phys. Lett. 86,111116 (2005). [2] T. Nagy, M. Forster, and P. Simon, Appl. Opt. 47, 3264 (2008).

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