THESIS presented at École Polytechnique to obtain the degree of DOCTOR OF ECOLE POLYTECHNIQUE specialization : physics by Nikolaos Kontogiannopoulos Title of the thesis : X-ray spectroscopic characterization of laser–produced hot dense plasmas defended publicly in 6 December 2007 in front of the jury composed of : Jean–Claude Gauthier President Anne Sylvie Gary Referee Jean–Francois Wyart Referee Patrick Audebert Victor Malka Claude Chenais–Popovics Invited Michel Poirier Research Director Acknowledgements This thesis was realized in the laboratory LULI (“Laboratoire pour l’Utilisation des Lasers Intenses”) of Ecole Polytechnique between 2004 and 2007. I would like to thank Francois Amiranoff director of laboratory for providing all the technical and material support and resources for implementing this work. I thank all the members of the jury. Especially Anne Sylvie Gary and Jean–Francois Wyart who carried out the demanding work of being referees. Also, Jean–Claude Gauthier, Patrick Audebert and Victor Malka, who accepted to judge this work. This work had the particular advantage to be accomplished, having as directors Claude Chenais–Popovics and Michel Poirier, which I gratefully thanks for their continuous help in every different problem that I found during my thesis. My gratitude to the members of research group that I had the pleasure to work with : Serena Bastiani–Ceccoti, Jean–Raphael Marques, and Olivier Peurysse. Special thanks to Thomas Blenski the theoretical work of which was a invaluable support in accomplishing my thesis. My grateful thanks to Frederic Thais. Apart from physics, its humor and its positive view gave to me a real reference to continue over the difficulties that I found during this work. I would also like to thanks all the PhD students, researchers and technicians for making this laboratory a pleasant place to work in. My special thanks to the PhD students Livia Lancia and Ana Mancic for the constructive discussions and fruitful collaboration that we had. N. Kontogiannopoulos Paris 2007 Contents Contents Introduction.......................................................................................................................................... v Chapter 1 Elements of plasma atomic physics............................................................................. 1 1.1 Introduction ................................................................................................................................ 1 1.2 Plasma atomic processes ........................................................................................................... 1 1.2.1 Detailed balance principle ................................................................................................. 2 1.2.2 Bound–bound processes .................................................................................................... 2 1.2.3 Bound–free processes......................................................................................................... 3 1.2.4 Free–free processes (Bremsstrahlung radiation) .............................................................. 5 1.3 Plasma statistical physics.......................................................................................................... 5 1.3.1 Local Thermodynamic Equilibrium................................................................................. 5 1.3.2 Non–Local Thermodynamic Equilibrium–Collisional Radiative Model.................... 7 1.4 Calculation of complex plasma spectrum–Superconfigurations approach....................... 7 1.5 Atomic codes of plasma physics.............................................................................................. 9 1.5.1 The code HULLAC............................................................................................................. 9 1.5.2 The code SCO .................................................................................................................... 11 1.5.3 The code TRANSPEC/AVERROES ............................................................................... 12 References of Chapter 1................................................................................................................. 14 Chapter 2 Radiation transfer through a plasma–Cavities thermal radiation and solid foil heating ................................................................................................................................................. 17 2.1 Introduction .............................................................................................................................. 17 2.2 Radiation transfer problem..................................................................................................... 17 2.2.1 Hydrodynamics–radiation equations coupling ........................................................... 17 2.2.2 MULTI one dimensional radiation hydrodynamic code ............................................ 22 2.3 Radiation confinement in the interior of an open spherical gold cavity.......................... 24 2.3.1 Energy exchange in the cavity interior .......................................................................... 25 2.3.2 Radiation reemission of the cavity wall–Basko scaling law ....................................... 27 2.3.3 Total radiation flux coupled with the absorption foil ................................................. 29 References of Chapter 2................................................................................................................. 31 Chapter 3 Laser and Instrumentation.......................................................................................... 33 3.1 Introduction .............................................................................................................................. 33 3.2 LULI2000 laser facility............................................................................................................. 33 3.2.1 Laser beam chains............................................................................................................. 33 3.2.2 Focalization of the laser beam–KDP crystal and random phase plate...................... 34 3.3 Targets description .................................................................................................................. 36 3.3.1 Gas–jet for spectral emission characterization.............................................................. 36 3.3.2 Spherical gold cavity for absorption spectra measurements...................................... 37 3.4. Diagnostic instruments .......................................................................................................... 38 3.4.1 Bragg crystal spectrograph.............................................................................................. 38 3.4.2 Transmission grating XUV spectrograph...................................................................... 43 3.4.3 Thomson scattering diagnostic ....................................................................................... 51 3.5 Auxiliary devices and other diagnostics............................................................................... 53 3.5.1 Streak Camera ................................................................................................................... 53 i Contents 3.5.2 CCD Cameras.................................................................................................................... 58 3.5.3 Kodak DEF film................................................................................................................. 59 3.5.4 Pinhole cameras ................................................................................................................ 61 3.5.5 Streak camera differential pumping system................................................................. 62 References of Chapter 3................................................................................................................. 64 Chapter 4 X–ray emission spectroscopy of xenon and krypton plasmas in NLTE conditions............................................................................................................................................ 67 4.1 Introduction .............................................................................................................................. 67 4.2 Experimental setup .................................................................................................................. 68 4.2.1 Laser beam and gas–jet targets ....................................................................................... 68 4.2.2 Diagnostic instruments .................................................................................................... 69 4.3 X–ray spectra data processing................................................................................................ 70 4.3.1 Emission spectra in the keV range ................................................................................. 70 4.3.2 XUV emission spectra ...................................................................................................... 74 4.4 Determination of the plasma parameters–Thomson scattering spectra analysis ........... 78 4.4.1 Helium plasma parameters ............................................................................................. 78 4.4.2 Xenon and krypton plasmas parameters....................................................................... 80 4.5 Characterization of the x–ray emission