- Overview of Atomic and Radiation Physics
Arati Dasgupta, Naval Research Laboratory More info ↓
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Abstract
The unexpected discovery of X rays by Roentgen in 1895 in Wurzburg, Germany, is the beginning of the story of ionizing radiation in modern physics. Since then, there has been a virtual explosion in the number and variety of high-power radiation sources at facilities around the world. Knowledge of atomic physics is the key to the generation and propagation of this radiation. By carefully modeling the interaction between matter and radiation, an enhanced understanding of matter created under extreme conditions of temperatures and densities can be obtained. I will give an overview of the many applications of atomic and radiation physics modeling from laboratory produced High Energy Density (HED) plasmas to cosmic plasmas. Atomic and radiation modeling of these dense plasmas will be highlighted in this talk, with a special emphasis on spectral diagnostics.
Biographical Summary
Arati Dasgupta
Naval Research Laboratory
Arati Dasgupta is a leading interdisciplinary atomic and plasma physicist whose research spans pulsed power radiation sources, inertial confinement fusion, laser-matter interaction, astrophysics and lighting. Dr. Dasgupta is a world expert in theoretical spectroscopy and in the dynamical behavior of non-local thermodynamic equilibrium (non-LTE) plasmas. Her benchmark atomic models have had significant impact on the understanding of experiments at major national facilities including nested-wire and gas-puff implosions on the Z facility at the Sandia National Laboratories and the first quantitative X-ray photo-pumping experiment utilizing the LCLS free electron laser. She is a fellow of American Physical Society and chair of the Women in Plasma Physics Committee. She is the author of an essay in the book titled “Blazing the Trail-Essays by leading women in science” to inspire young women contemplating career in science.
- Radiation Transport in Z pinches
John P. Apruzese, NRL/L3 More info ↓
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Abstract
This talk will begin with a brief description of the theory of radiation transport; the conditions where it is a reasonable approximation as well as its limitations relating to the true quantum properties of photons. Physical processes that are responsible for opacity in Z pinches will then be covered, and insights into the nature of the transport process, which can be gained from escape probability concepts will be presented. Discussions of local vs. non-local thermodynamic equilibrium, conditions required for those states, and transition to the blackbody limit will follow. This segment of the minicourse will conclude with examples of Z-pinch experiments that demonstrate effects of opacity.
Biographical Summary
John P. Apruzese
Naval Research Laboratory
Dr. Apruzese is a leader in the physics and numerical simulation of radiation transport. His work, which has been reported in nearly 200 publications, has lead to enhancements in the power and energy of x-ray sources, and numerous advances in plasma spectroscopy and diagnostics. He has also developed efficient numerical methods which have led to large reductions in the computation time required for realistic calculations of radiation transport. He is a Fellow of the American Physical Society and in 2001 was named by that Society as a Distinguished Lecturer in Plasma Physics.
- X-Ray Spectroscopic Signatures for Z pinches
Alla Safronova, Univ. Nevada, Reno More info ↓
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Abstract
University-scale Z-pinch generators are able to produce HED plasmas with a broad range of temperatures, densities, and opacity properties. X-ray spectroscopy is an excellent tool to learn parameters and evolution of such plasmas. The talk begins with a brief description of atomic processes including X-ray line polarization and then moves to non-LTE calculations and importance of EBIT data for benchmarking of atomic data. The examples of X-ray K-, L-, and M-shell spectra produced on 1 MA generator and their interpretation will be considered. The talk will be concluded with discussion on how different are X-ray spectra on much larger Z-pinch generators?
Biographical Summary
Alla Safronova
University of Nevada, Reno
Alla Safronova is a Research Professor at University of Nevada, Reno where she teaches Quantum and Statistical Mechanics classes and has a research group which is very active in studying radiation from HED Plasmas such as Z-pinch and high-power laser plasmas. She is one of the pioneers in the application of X-ray line polarization to astrophysical and laboratory plasmas. She is working in both theoretical atomic and plasma physics and has published about 200 articles. Her former PhD students are employed at SNL, NRL, and also at universities abroad. She organizers series of RHEDP workshops focused on student participation.
- Applied Spectroscopy in Pulsed Power Plasmas
Gregory A. Rochau, Sandia National Lab More info ↓
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Abstract
Applied spectroscopy is a powerful diagnostic tool for high energy density plasmas produced with modern pulsed power facilities. These facilities create unique plasma environments with a broad range of electron densities (1013 – 1023 cm−3) and temperatures (100 – 103 eV) immersed in strong magnetic (> 100 T) and electric (up to 1 GV/m) fields. This lecture surveys the application of plasma spectroscopy to diagnose a variety of plasma conditions generated by pulsed power sources including: magnetic field penetration into plasma, measuring the time-dependent spatial distribution of 1 GV/m electric-fields, opacity measurements approaching stellar interior conditions, characteristics of a radiating shock propagating at 330 km/s, and determination of plasma conditions in imploded capsule cores at 150 Mbar pressures. These applications provide insight into fundamental properties of nature in addition to their importance for addressing challenging pulsed power science problems.
Biographical Summary
Dr. Gregory A. Rochau
Sandia National Laboratories
Dr. Greg Rochau is a leader in the field of experimental spectroscopy as applied to the study of high energy density plasmas. He has served as principal investigator for numerous experiments on the Z Facility at Sandia National Laboratories as well as on the OMEGA laser facility at the University of Rochester Laboratory for Laser Energetics. This research, which is published in over 50 journal articles during his young career, is focused on the study of fusion plasmas and the interaction of radiation with matter at extreme conditions. Presently, Dr. Rochau manages the applied radiation sciences effort on the Z Facility while continuing to develop new diagnostic systems and methods for the spectroscopic investigation of high temperature, high density plasmas.
- Opacity: Theoretical and Astrophysical Aspects
Anil K. Pradhan, Ohio State University More info ↓
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Abstract
Opacity is the fundamental microscopic quantity that governs the flow of radiation in plasma. All atomic and radiation processes play a role over a vast temperature-density regime. There are important similarities, and crucial spatial and temporal differences, between astrophysical and laboratory high-energy-density (HED) plasma environments. The local thermodynamic equilibrium (LTE) vs. non-LTE dichotomy manifests itself strongly, although the basic atomic physics of opacities may be applicable to both. This lecture will cover a) astrophysical and HED plasmas, b) stellar structure, properties, abundances, c) atomic processes, d) opacity computation methodologies, e) theoretical models and experiments, f) current status and future prospects, and g) astrophysical and laboratory applications.
Biographical Summary
Anil Pradhan
Ohio State University
Anil Pradhan is a Professor of Astronomy, Chemical Physics, and Biophysics. Dr. Pradhan is the leader of a multi-disciplinary research group and he is an international expert on theoretical atomic physics relevant for astrophysical and laboratory plasmas. His state-of-the-art research on opacity calculations has had major impact in understanding solar opacities and abundances. He is the author of 175 refereed journal and 50 review articles. Among his various recognitions, he is a fellow of American Physical Society, director of US-India STEM Education and Research Faculty Training Project, recipient of a Fulbright-Nehru Distinguished Fellowship in Teaching and Research, and co-author of a textbook titled “Atomic Astrophysics and Spectroscopy”, Cambridge University Press (2011). See http://www.astronomy.ohio-state.edu/~pradhan/
- Radiation Field Effects on Non-LTE Plasmas
Steven Rose, Imperial College, UK More info ↓
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Abstract
In this talk we will consider the effect of an ambient radiation field on the state of bound-electron excitation and ionisation in a non-LTE high energy density plasma. We look at both broad and narrowband radiation fields and at both experiments and theory. We will pay particular attention to the direct influence that the radiation field has on the population of the different states through processes in which a photon in the radiation field is absorbed or emitted by these states.
Biographical Summary
Steven James Rose
Imperial College, London
Steven Rose is Professor of Plasma Physics and the Vice-Dean of the Faculty of Natural Sciences at Imperial College, London. He has worked in plasma physics for all of his career, with a particular emphasis on plasmas produced using high-power lasers. He has spent much of that time at the two high-power laser facilities in the UK: the Rutherford Appleton Laboratory’s Central Laser Facility where he became the Associate Director for Physics and at AWE Aldermaston where he was the Head of Plasma Physics.
- Line Profile and Line Broadening
Richard W. Lee, SLAC/UC-Berkeley More info ↓
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Abstract
This lecture will cover I) The importance and role of spectral line profiles in a) formation of opacity, b) diagnosis of plasma properties, c) radiation transport, and d) the theoretical aspects of spectral lines; II) Theoretical formulation for spectral line profiles illustrating a) the concept of separation of ion and electron broadening mechanisms and formation of spectral lines in simplest case b) additional mechanisms such as atomic structure, natural broadening, Doppler Broadening, magnetic field effects and instrumental broadening affecting the line shape, and c) predictive aspects of the current theories for laser-plasma and Tokamak modeling, applications for pulsed Power, inertial Fusion and high Z materials; and III) The future of line shape theory and applications in a) improving speed for large-scale problems: the role of High-Z, b) radiation redistribution calculations: brief status report, and c) dynamic ions and Static ions.
Biographical Summary
Richard W. Lee
SLAC/UC-Berkeley
Educated at the Johns Hopkins University and receiving his Ph.D. in Physics in 1970 from University of Florida, he then did post-doctoral research at Imperial College, London. He joined the faculty in at Imperial College in 1972 leaving in 1984 for Lawrence Livermore National Laboratory. During this period he developed techniques, now widely used, to analyze the radiative properties of hot dense matter laboratory plasmas. In 1980’s he became the leader for applied physics experiments on high-energy lasers at LLNL and continued to develop theoretical techniques for plasma spectroscopy. During this period he became an Associate Editor for Journal of Quantitative Spectroscopy and Radiative Transfer specializing in the area of High Energy density research. He is current leading the development of High Energy Density research on the 4th generation x-ray light sources in Europe and the United States. He is now the Associate Director of the University of California Institute for Material Dynamics in Extreme Conditions and the Editor-in-Chief of the journal “High energy Density Physics” launched in December 2005.
- Non-LTE Atomic Physics for the National Ignition Facility – a Tour of X-Ray Spectra
Kevin B. Fournier, Lawrence Livermore National Laboratory More info ↓
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Abstract
The non-local thermodynamic equilibrium (non-LTE) state of matter is ubiquitous in the universe everywhere physical systems are continuously and discontinuously subject to flux of matter and energy to and from other systems. The National Ignition Facility (NIF) is the world’s highest energy laser and is an international user facility dedicated to pursing inertial confinement fusion (ICF) and fundamental research. The states of matter studies at the NIF are governed by non-LTE exchanges between matter and radiation fields. I will describe energy balance in and measured x-ray spectra from a variety of NIF targets. I'll talk generally about issues of accuracy in atomic codes when computing the detailed emissivities of high-Z radiators.
Biographical Summary
Kevin B. Fournier
Lawrence Livermore National Laboratory
Kevin Fournier is a senior physicist in the Inertial Confinement Fusion and High-Energy Density Science group at the National Ignition Facility at the Lawrence Livermore National Laboratory. He runs the NIF work-for-others program that designs and executes experiments for government agencies outside the Department of Energy. Dr. Fournier’s group creates high photon energy, high flux x-ray environments for x-ray-matter-interaction studies, x-ray imaging applications, and x-ray transport studies. Dr. Fournier’s group also develops x-ray spectrometers as diagnostic capability for all ICF, HED and fundamental science experiments at the NIF. Dr. Fournier is a recognized expert in laser interactions with ultra-low-density matter.
- Atomic Models for Non-LTE Simulations
Yuri Ralchenko, NIST More info ↓
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Abstract
Reliable studies of astrophysical and laboratory plasmas far from the local thermodynamic equilibrium (LTE) necessarily involve analysis of physical processes affecting ionization balance and population distributions among atomic states. This lecture will highlight the basic principles in construction and application of atomic models for non-LTE plasmas. A number of topics, e.g., availability and quality of atomic data and comparisons of different atomic models, will be discussed in detail. The examples of NLTE applications will range from low-density non-Maxwellian plasmas of EBITs to neutral beams in magnetic fusion to laser-produced plasmas. A short introduction to the online collisional-radiative code FLYCHK (http://nlte.nist.gov/FLY) will be given as well.
Biographical Summary
Yuri Ralchenko
National Institute of Standards and Technology
Yuri Ralchenko is the Leader of the Atomic Spectroscopy Group at the National Institute of Standards and Technology. His scientific interests include plasma spectroscopy, collisional-radiative modeling of laboratory and astrophysical plasmas, high-precision atomic physics of highly-charged ions, generation of atomic data and development of atomic databases. Dr. Ralchenko is a Fellow of the American Physical Society and the Chairman of the series of NLTE Code Comparison Workshops.
- Science at the Timescale of the Electron: Coherent keV X-Rays from Tabletop Femtosecond Lasers
Margaret Murnane, JILA/ Univ. Colorado More info ↓
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Abstract
Since the invention of the laser, scientists have been striving to extend coherent light into the X-ray region. Very recently, because of a new ability to manipulate electrons on their natural, attosecond, time-scales, the dream of realizing bright, laser-like, X-ray beams on a tabletop with photon energies >1.6keV (wavelengths <8Å) has become a reality. This course will review high harmonic generation from femtosecond lasers. Next it will discuss how to optimize the spectral and temporal characteristics of this light source for different applications. Finally, selected applications in atomic and plasma science and imaging will be highlighted.
Biographical Summary
Margaret M. Murnane
University of Colorado
Margaret Murnane is a Fellow of JILA and a Distinguished Professor in Physics at the University of Colorado. She runs a joint, multi-disciplinary, research group with her husband, Prof. Henry Kapteyn. Prof. Murnane uses coherent beams of laser and x-ray light to capture the fastest dynamics in molecules and materials at the nanoscale. She is a Fellow of the Optical Society of America, the American Physical Society, and the AAAS. She was elected to the National Academy of Sciences, and the American Academy of Arts and Sciences. She was awarded a John D. and Catherine T. MacArthur Fellowship, the Schawlow Prize of the American Physical Society, and the R.W. Wood Prize of the Optical Society of America.
- Properties of Ultrafast Laser Heated Plasmas
Todd Ditmire, Univ. Texas More info ↓
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Abstract
High peak power, femtosecond lasers enable creation of unique, high temperature, high pressure states of matter in the lab. By heating solids on time scales faster than that solid can expand, solid density matter of temperatures from 1 eV to 1 keV can be accessed. This lecture will explore the properties of such isochorically heated matter, including the equation of state, conductivity and ionization state properties of these strongly coupled and sometimes degenerate plasmas. This lecture will also present the physics behind the various experimental techniques used to create these plasmas, including direct laser heating, proton and x-ray heating. Finally, the lecture will discuss techniques for diagnosing such isochorically heated targets.
Biographical Summary
Todd Ditmire
University of Texas
Todd Ditmire is Professor of Physics at the University of Texas at Austin where he is the director of the Center for High Energy Density Science, a DoE NNSA funded Center of Excellence devoted to research in laser driven HED physics. His research involves the production and study of plasmas produced by intense irradiation of solids, gasses and atomic clusters. These studies use very high peak power lasers, including the Texas Petawatt laser which Todd designed and developed at UT. His research interests include study of the state properties of laser heated matter, shock waves in these targets and radiation production. He is a Fellow of the American Physical Society. He is also President of National Energetics, Inc., an Austin based company which produces large scale custom high energy lasers.