13Th International Congress on Plasma Physics (ICPP 2006) BOOK
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Our Dynamic Sun: 2017 Hannes Alfvén Medal Lecture at the EGU
Ann. Geophys., 35, 805–816, 2017 https://doi.org/10.5194/angeo-35-805-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. Our dynamic sun: 2017 Hannes Alfvén Medal lecture at the EGU Eric Priest1,* 1Mathematics Institute, St Andrews University, St Andrews KY16 9SS, UK *Invited contribution by Eric Priest, recipient of the EGU Hannes Alfvén Medal for Scientists 2017 Correspondence to: Eric Priest ([email protected]) Received: 15 May 2017 – Accepted: 12 June 2017 – Published: 14 July 2017 Abstract. This lecture summarises how our understanding 1 Introduction of many aspects of the Sun has been revolutionised over the past few years by new observations and models. Much of the Thank you most warmly for the award of the Alfvén Medal, dynamic behaviour of the Sun is driven by the magnetic field which gives me great pleasure. In addition to a feeling of since, in the outer atmosphere, it represents the largest source surprise, I am also deeply humbled, because Alfvén was one of energy by far. of the greats in the field and one of my heroes as a young The interior of the Sun possesses a strong shear layer at the researcher (Fig. 1). We need dedicated scientists who fol- base of the convection zone, where sunspot magnetic fields low a specialised topic with tenacity and who complement are generated. A small-scale dynamo may also be operating one another in our amazingly diverse field; but we also need near the surface of the Sun, generating magnetic fields that time and space for creativity in this busy world, especially thread the lowest layer of the solar atmosphere, the turbulent for those princes of creativity, mavericks like Alfvén who can photosphere. -
Large-Scale Periodic Solar Velocities
LARGE-SCALE PERIODIC SOLAR VELOCITIES: AN OBSERVATIONAL STUDY (NASA-CR-153256) LARGE-SCALE PERIODIC SOLAR N77-26056 ElOCITIeS: AN OBSERVATIONAL STUDY Stanford Univ.) 211 p HC,A10/F A01 CSCL 03B Unclas G3/92 35416 by Phil Howard Dittmer Office of Naval Research Contract N00014-76-C-0207 National Aeronautics and Space Administration Grant NGR 05-020-559 National Science Foundation Grant ATM74-19007 Grant DES75-15664 and The Max C.Fleischmann Foundation SUIPR Report No. 686 T'A kj, JUN 1977 > March 1977 RECEIVED NASA STI FACILITY This document has been approved for public INPUT B N release and sale; its distribution isunlimited. 4 ,. INSTITUTE FOR PLASMA RESEARCH STANFORD UNIVERSITY, STANFORD, CALIFORNIA UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) DREAD INSTRUCTIONS REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM I- REPORT NUMBER 2 GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER SUIPR Report No. 686 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED Large-Scale Periodic Solar Velocities: Scientific, Technical An Observational Study 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) 8 CONTRACT OR GRANT NUMBER(s) Phil Howard Dittmer N00014-76-C-0207 S PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK Institute for Plasma Research AREA & WORK UNIT NUMBERS Stanford University Stanford, California 94305 12. REPORT DATE . 13. NO. OF PAGES 11. CONTROLLING OFFICE NAME AND ADDRESS March 1977 211 Office of Naval Research Electronics Program Office 15. SECURITY CLASS. (of-this report) Arlington, Virginia 22217 Unclassified 14. MONITORING AGENCY NAME & ADDRESS (if diff. from Controlling Office) 15a. DECLASSIFICATION/DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT (of this report) This document has been approved for public release and sale; its distribution is unlimited. -
Scientists Propose Source of Unexplained Solar Jets 8 July 2021, by Raphael Rosen
Scientists propose source of unexplained solar jets 8 July 2021, by Raphael Rosen was an undergraduate at Princeton University. He currently is a doctoral student in the Nuclear Engineering and Radiological Sciences department at the University of Michigan. Large coronal jets, though originating 93 million miles away on the sun, can affect us here on Earth. The jets can contribute to outpourings of particles known as the solar wind that can strike our planet's outer atmosphere and interfere with communications satellites and power grids. Smaller jets, which are studied at PPPL, also contribute to the solar wind, and along with bursts of X-ray light can help heat the corona. Any insights into how the jets form could help scientists to predict their occurrence and prepare Earth for their impact. Graduate student Joshua Latham with computer- generated images of magnetic field lines and plasma on The simulations indicate that a dome-shaped the sun. Credit: Elle Starkman magnetic structure forms on the sun's surface prior to the coronal jets. Then, magnetic field lines at the bottom of the structure detach from the solar surface in a process known as magnetic Nothing seems more familiar than the sun in the reconnection, the breaking apart and violent sky. But mysterious swirls, jets, and flashes of reconnection of magnetic fields that occurs powerful light that scientists cannot explain occur throughout the universe. in the sun's outer atmosphere all the time. Now, researchers at the U.S. Department of Energy's Now the dome begins to tilt. As it does so, the top (DOE) Princeton Plasma Physics Laboratory magnetic field lines touch the surrounding lines and (PPPL) have gained insight into these puzzling create another round of reconnection. -
GSFC Heliophysics Science Division 2009 Science Highlights
NASA/TM–2010–215854 GSFC Heliophysics Science Division 2009 Science Highlights Holly R. Gilbert, Keith T. Strong, Julia L.R. Saba, and Yvonne M. Strong, Editors December 2009 Front Cover Caption: Heliophysics image highlights from 2009. For details of these images, see the key on Page v. The NASA STI Program Offi ce … in Profi le Since its founding, NASA has been ded i cated to the • CONFERENCE PUBLICATION. Collected ad vancement of aeronautics and space science. The pa pers from scientifi c and technical conferences, NASA Sci en tifi c and Technical Information (STI) symposia, sem i nars, or other meetings spon sored Pro gram Offi ce plays a key part in helping NASA or co spon sored by NASA. maintain this impor tant role. • SPECIAL PUBLICATION. Scientifi c, techni cal, The NASA STI Program Offi ce is operated by or historical information from NASA pro grams, Langley Research Center, the lead center for projects, and mission, often concerned with sub- NASAʼs scientifi c and technical infor ma tion. The jects having substan tial public interest. NASA STI Program Offi ce pro vides ac cess to the NASA STI Database, the largest collec tion of • TECHNICAL TRANSLATION. En glish-language aero nau ti cal and space science STI in the world. trans la tions of foreign scien tifi c and techni cal ma- The Pro gram Offi ce is also NASAʼs in sti tu tion al terial pertinent to NASAʼs mis sion. mecha nism for dis sem i nat ing the results of its research and devel op ment activ i ties. -
Peter E Williamsl , William Dean Pesnell Title
ABSTRACT FINAL ID: SH23D-03; TITLE: Time-Series Analyses of Supergranule Characteristics Compared Between SDO/HMI, SOHO/MDI and Simulated Datasets. SESSION TYPE: Oral SESSION TITLE: SH23D. The Sun and the Heliosphere During the Solar Cycle 23/24 Minimum II l l AUTHORS (FIRST NAME, LAST NAME): Peter E Williams , William Dean Pesnell INSTITUTIONS (ALL): 1. Code 671, NASAIGSFC, Greenbelt, MD, United States. Title of Team: ABSTRACT BODY: Supergranulation is a well-observed solar phenomenon despite its underlying mechanisms remaining a mystery. Originally considered to arise due to convective motions, alternative mechanisms have been suggested such as the cumulative downdrafts of granules as well as displaying wave-like properties. Supergranule characteristics are well documented, however. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 mis, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for more than half a century, their existence is also observed in other datasets such as magneto grams and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) continues to produce Doppler images enabling the continuation of supergranulation studies made with SOHO/MDI, but with superior temporal and spatial resolution. The size-distribution of divergent cellular flows observed on the photosphere now reaches down to granular scales, allowing contemporaneous comparisons between the two flow components. -
MRX Research in the Context of Princeton Max-Planck Collaboration
MRX research in the context of Princeton Max-Planck collaboration Masaaki Yamada Princeton Plasma Physics laboratory Princeton University January 14, 2013 With MRX Staff: H. Ji, R. Kulsrud, E. Lawrence, T. Tharp + Graduate students Magnetic Reconnection • Topological rearrangement of magnetic field lines! • Magnetic energy => Kinetic energy! • Key to stellar flares, coronal heating, particle acceleration, star formation, energy loss in lab plasmas! Before reconnection After reconnection Outline! !Magnetic reconnection! – Leading issue in space, astro- and fusion plasma physics" –! A major question was: Why does it occur so fast?" –! New question: How does energy flow from magnetic field to plasmas?" •! Generation of a reconnection layer on MRX => Local analysis" •! Two fluid physics analysis! Recent Emphasis:! •! Energy conversion processes from B2 to ions and electrons! •! A new series of experimental campaign and the recent results! –! Plasma jog experiment: Addresses heating and acceleration of ions and electrons" –! Guide field effects on two-fluid reconnection" –! Reconnection in partially ionized plasmas" –! Solar flare relevant plasma arcs" Plans for Princeton-MPPC collaboration! Magnetic Reconnection Experiment Primary objectives of MRX is to create a proto-typical reconnection layer and study it experimentally with cross- validation with numerical simulations Experimentally measured flux evolution! 13 -3 ne= 1-10 x10 cm , ! Te~5-15 eV, ! B~100-500 G, ! S < 1000! Reconnection layer Profile changes with Collisionality: Experimentally measured field line features in MRX •! Manifestation of Hall effects •! Electrons would pull magnetic field lines with their flow Two-fluid physics dictates reconnection layer dynamics (a) (b) R •! Out of plane magnetic field is generated during reconnection. •! Electron acceleration and heating with mirror- Plasma Electron Outflow trapped electrons. -
Frontiers in Plasma Physics Research: a Fifty-Year Perspective from 1958 to 2008-Ronald C
• At the Forefront of Plasma Physics Publishing for 50 Years - with the launch of Physics of Fluids in 1958, AlP has been publishing ar In« the finest research in plasma physics. By the early 1980s it had St t 5 become apparent that with the total number of plasma physics related articles published in the journal- afigure then approaching 5,000 - asecond editor would be needed to oversee contributions in this field. And indeed in 1982 Fred L. Ribe and Andreas Acrivos were tapped to replace the retiring Fran~ois Frenkiel, Physics of Fluids' founding editor. Dr. Ribe assumed the role of editor for the plasma physics component of the journal and Dr. Acrivos took on the fluid Editor Ronald C. Davidson dynamics papers. This was the beginning of an evolution that would see Physics of Fluids Resident Associate Editor split into Physics of Fluids A and B in 1989, and culminate in the launch of Physics of Stewart J. Zweben Plasmas in 1994. Assistant Editor Sandra L. Schmidt Today, Physics of Plasmas continues to deliver forefront research of the very Assistant to the Editor highest quality, with a breadth of coverage no other international journal can match. Pick Laura F. Wright up any issue and you'll discover authoritative coverage in areas including solar flares, thin Board of Associate Editors, 2008 film growth, magnetically and inertially confined plasmas, and so many more. Roderick W. Boswell, Australian National University Now, to commemorate the publication of some of the most authoritative and Jack W. Connor, Culham Laboratory Michael P. Desjarlais, Sandia National groundbreaking papers in plasma physics over the past 50 years, AlP has put together Laboratory this booklet listing many of these noteworthy articles. -
CESRA Workshop 2019: the Sun and the Inner Heliosphere Programme
CESRA Workshop 2019: The Sun and the Inner Heliosphere July 8-12, 2019, Albert Einstein Science Park, Telegrafenberg Potsdam, Germany Programme and abstracts Last update: 2019 Jul 04 CESRA, the Community of European Solar Radio Astronomers, organizes triennial workshops on investigations of the solar atmosphere using radio and other observations. Although special emphasis is given to radio diagnostics, the workshop topics are of interest to a large community of solar physicists. The format of the workshop will combine plenary sessions and working group sessions, with invited review talks, oral contributions, and posters. The CESRA 2019 workshop will place an emphasis on linking the Sun with the heliosphere, motivated by the launch of Parker Solar Probe in 2018 and the upcoming launch of Solar Orbiter in 2020. It will provide the community with a forum for discussing the first relevant science results and future science opportunities, as well as on opportunity for evaluating how to maximize science return by combining space-borne observations with the wealth of data provided by new and future ground-based radio instruments, such as ALMA, E-OVSA, EVLA, LOFAR, MUSER, MWA, and SKA, and by the large number of well-established radio observatories. Scientific Organising Committee: Eduard Kontar, Miroslav Barta, Richard Fallows, Jasmina Magdalenic, Alexander Nindos, Alexander Warmuth Local Organising Committee: Gottfried Mann, Alexander Warmuth, Doris Lehmann, Jürgen Rendtel, Christian Vocks Acknowledgements The CESRA workshop has received generous support from the Leibniz Institute for Astrophysics Potsdam (AIP), which provides the conference venue at Telegrafenberg. Financial support for travel and organisation has been provided by the Deutsche Forschungsgemeinschaft (DFG) (GZ: MA 1376/22-1). -
Study on Effect of Radiative Loss on Waves in Solar Chromosphere
Master Thesis Study on effect of radiative loss on waves in solar chromosphere Wang Yikang Department of Earth and Planetary Science Graduate School of Science, The University of Tokyo September 4, 2017 Abstract The chromospheric and coronal heating problem that why the plasma in the chromosphere and the corona could maintain a high temperature is still unclear. Wave heating theory is one of the candidates to solve this problem. It is suggested that Alfven´ wave generated by the transverse motion at the photosphere is capable of transporting enough energy to the corona. During these waves propagating in the chromosphere, they undergo mode conver- sion and generate longitudinal compressible waves that are easily steepening into shocks in the stratified atmosphere structure. These shocks may contribute to chromospheric heating and spicule launching. However, in previous studies, radiative loss, which is the dominant energy loss term in the chromosphere, is usually ignored or crudely treated due to its difficulty, which makes them unable to explain chromospheric heating at the same time. In our study, based on the previous Alfven´ wave driven model, we apply an advanced treatment of radiative loss. We find that the spatial distribution of the time averaged radiative loss profile in the middle and higher chromosphere in our simulation is consistent with that derived from the observation. Our study shows that Alfven´ wave driven model has the potential to explain chromospheric heating and spicule launching at the same time, as well as transporting enough energy to the corona. i Contents Abstract i 1 Introduction 1 1.1 General introduction . .1 1.2 Radiation in the chromosphere . -
Structure of the Electron Diffusion Region in Magnetic Reconnection with Small Guide Fields
Structure of the electron diffusion region in magnetic reconnection with small guide fields MASSA0HU- by Jonathan Ng JAN I Submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2012 @ Jonathan Ng, MMXII. All rights reserved. The author hereby grants to MIT permission to reproduce and distribute publicly paper and electronic copies of this thesis document in whole or in part. Author ............ Department of Physics May 11, 2012 / / Certified by..... *2) Jan Egedal-Pedersen Associate Professor of Physics Thesis Supervisor Accepted by ...... .............. ........ ............. ... Nergis Mavalvala Senior Thesis Coordinator, Department of Physics 2 Structure of the electron diffusion region in magnetic reconnection with small guide fields by Jonathan Ng Submitted to the Department of Physics on May 11, 2012, in partial fulfillment of the requirements for the degree of Bachelor of Science in Physics Abstract Observations in the Earth's magnetotail and kinetic simulations of magnetic reconnec- tion have shown high electron pressure anisotropy in the inflow of electron diffusion regions. This anisotropy has been accurately accounted for in a new fluid closure for collisionless reconnection. By tracing electron orbits in the fields taken from particle-in-cell simulations, the electron distribution function in the diffusion region is reconstructed at enhanced resolutions. For antiparallel reconnection, this reveals its highly structured nature, with striations corresponding to the number of times an electron has been reflected within the region, and exposes the origin of gradients in the electron pressure tensor important for momentum balance. The addition of a guide field changes the nature of the electron distributions, and the differences are accounted for by studying the motion of single particles in the field geometry. -
Rotational Effects on Supergranulation- a Survey
International Journal of Research and Scientific Innovation (IJRSI) | Volume IV, Issue X, October 2017 | ISSN 2321–2705 Rotational Effects on Supergranulation- A Survey Sowmya G M1, Rajani G1, Yamuna M1, Paniveni Udayshankar2, R Srikanth3, Jagdev Singh4 1GSSS Institute of Engineering & Technology for Women, KRS Road, Meragalli Mysuru-570016, Karnataka, India 2Inter-University Centre for Astronomy and Astrophysics, Pune, India 3Poornaprajna Institute of Scientific Research, Devanahalli, Bangaluru-562110, Karnataka, India 4 Indian Institute of Astrophysics, Koramangala, Bangalore, Karnataka, India Abstract: - Supergranules are large-scale convection cells in the Supergranules are characterized by the three parameters, high solar photosphere that are seen at the surface of the Sun as namely length L, lifetime T and horizontal flow velocity a pattern of horizontal flows. They are approximately 30,000 (Paniveni et al. 2004; Paniveni et al. 2011). Supergranules kilometres in diameter and have a lifespan of about 24 hours. were discovered in the 1950’s by Hart (1954) but were studied About 5000 of them are seen at any point of time in the upper in detail in the 1960’s by Leighton et al. (1962), who gave photospheric region. A great deal of observational data and theoretical understanding is now available in the field of them their name. Leighton et al. (1962) showed that this supergranulation. In this paper, we review the literature on the cellular pattern of horizontal flows covers the solar surface rotational effect of the supergranules and its relation to the solar and that the boundaries of the cells coincide with the dynamo model. chromospheric/magnetic network (Raju et al. -
Cosmic Rays and the Earth's Atmosphere
COSMIC RAYS AND THE EARTH’S ATMOSPHERE A.D. Erlykin1,2 and A.W. Wolfendale2 1 P.N. Lebedev Physics Institute, Leninsky Prospekt, Moscow, Russia. 2 Department of Physics, University of Durham, South Road, Durham, DH1 3LE, U.K. Abstract Avery brief summary is given of aspects of cosmic ray physics which have rel- evance to the possible effects of cosmic rays on ‘climate’. It is concluded that a more detailed look at the effect of fast ionizing particles on the atmosphere from the standpoint of cloud production would be advantageous. 1. INTRODUCTION There have been many claims for a correlation between solar properties (e.g. sunspot number) and climate but all have suffered from the absence of a reasonable physical cause, the point being that the energy changes in the solar variations are deemed to be too small to account for the necessary climate forcing. This is not to say that there are no well-documented effects on very long time scale; there are. Those due to variations in the sun-earth distance and the inclination of the earth’s axis (Milankovic effects), which relate to 103 − 106 y periods, are generally agreed. What is not (yet) agreed is that the 11-year solar cycle has a significant correlation with climate. The best evidence favouring a specific cause for a sunspot (SS) — climate connection relates to the apparent role of cosmic rays which are, themselves, modulated by solar activity. The observation is that by the Danish group in which there is a correlation of cloud cover and CR intensity over the oceans.