Uv Thomson Scattering from X-ray Laser Plasmas PDF Download

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Languages : en
Pages : 6

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Author:
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Languages : en
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In this paper the authors demonstrate through calculations and theoretical analysis the first application of a x-ray laser for probing hot, high-density plasmas (n[sub e][ge] 10[sup 23] cm[sup -3]) using a Ni-like transient collisional excitation x-ray laser as a probe. Theoretical predictions are used to diagnose the electron temperature in short pulse (500 fs) laser produced plasmas. The threshold power of the x-ray probe is estimated by comparing theoretical scattering levels with plasma thermal emission. The necessary spectral resolution of the instrument sufficient for resolving electron temperature is given.

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Languages : en
Pages : 27

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We propose a collective Thomson scattering experiment at the VUV free electron laser facility at DESY (FLASH) which aims to diagnose warm dense matter at near-solid density. The plasma region of interest marks the transition from an ideal plasma to a correlated and degenerate many-particle system and is of current interest, e.g. in ICF experiments or laboratory astrophysics. Plasma diagnostic of such plasmas is a longstanding issue. The collective electron plasma mode (plasmon) is revealed in a pump-probe scattering experiment using the high-brilliant radiation to probe the plasma. The distinctive scattering features allow to infer basic plasma properties. For plasmas in thermal equilibrium the electron density and temperature is determined from scattering off the plasmon mode.

Author: Stéphane Sebban
Publisher: Springer Science & Business Media
ISBN: 3319006967
Category : Science
Languages : en
Pages : 305

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These proceedings comprise of invited and contributed papers presented at the 13th International Conference on X-Ray Lasers (ICXRL 2012) which was held 11–15 June 2012 in Paris, France, in the famous Quartier Latin, inside the historical Center of Cordeliers. This conference is part of a continuing series dedicated to recent developments and applications of x-ray lasers and other coherent x-ray sources with attention to supporting technologies and instrumentation. New results in the generation of intense coherent x-rays and progress towards practical devices and their applications are reported in these proceedings, including areas of research in plasma-based x-ray lasers, 4th generation accelerator-based sources and higher harmonic generation. Recent achievements related to the increase of the repetition rate up to 100 Hz and shorter wavelength collisional plasma-based soft x-ray lasers down to about 7 nm are presented. Seeding the amplifying plasma with a femtosecond high-order harmonic of infrared laser was foreseen as the required breakthrough to break the picosecond frontier. Numerical simulations based on the Maxwell-Bloch model are presented in these proceedings, transposing the chirped pulse amplification technique to the x-ray domain in order to increase the time over which the femtosecond seed can be amplified. These proceedings also include innovative applications of soft x–ray lasers based on techniques and diagnostics relevant to topical domains such as EUV lithography, inertial confinement fusion, or warm dense matter physics.

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Languages : en
Pages : 11

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We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with ≈200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 [mu]m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

Author: John Sheffield
Publisher: Academic Press
ISBN: 0080952038
Category : Science
Languages : en
Pages : 512

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This work presents one of the most powerful methods of plasma diagnosis in exquisite detail, to guide researchers in the theory and measurement techniques of light scattering in plasmas. Light scattering in plasmas is essential in the research and development of fusion energy, environmental solutions, and electronics. Referred to as the "Bible" by researchers, the work encompasses fusion and industrial applications essential in plasma research. It is the only comprehensive resource specific to the plasma scattering technique. It provides a wide-range of experimental examples and discussion of their principles with worked examples to assist researchers in applying the theory. Computing techniques for solving basic equations helps researchers compare data to the actual experiment New material on advances on the experimental side, such as the application of high density plasmas of inertial fusion Worked out examples of the scattering technique for easier comprehension of theory

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Languages : en
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Colliding Au, CD and Ti-Cr plasmas have been generated by illuminating two opposing foils each with a [approximately] 100J, 0.5 nsec, 2[omega] Nd-glass laser beam from the Trident laser facility at Los Alamos. The plasmas are being used to study plasma interactions which span the parameter regime from interpenetrating to collisional stagnation. X-ray emission during the laser target interaction and the subsequent collision is used to diagnose the initial plasma conditions and the colliding plasma properties. X-ray instrumentation consists of a 100 ps gated x-ray pinhole imager, a time-integratcd bremsstrahlung x-ray spectrograph and a gated x-ray spectrograph used to record isoelectronic spectra from the Ti-Cr plasmas. The imager has obtained multi-frame images of the collision and therefore, a measure of the stagnation length which is a function of the ion charge state and density and a strong function of the electron temperature. Other instrumentation includes a Thomson scattering spectrometer with probe beam, neutron detectors used to monitor the CD coated foil collisions and an ion spectrometer. We will describe the current status of the experiments and current results with emphasis on the x-ray emission diagnostics. We will also briefly describe the modeling using Lasnex and ISIS, a particle-in-cell code with massless fluid electrons and inter particle (classical) collisions.

Author: Jongmin Lee
Publisher: Springer Science & Business Media
ISBN: 9400711867
Category : Science
Languages : en
Pages : 368

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This book provides a thorough account of the current status of achievements made in the area of soft X-Ray laser source development and of the increasingly diverse applications being demonstrated using such radiation sources. There is significant effort worldwide to develop very bright, short duration radiation sources in the X-Ray spectral region – driven by the multitude of potential applications in all branches of science. This book contains updates on several different approaches for comparative purposes but concentrates on developments in the area of laser-produced plasmas, whereby transient population inversion and gain between ion states is pumped by optical lasers interacting with pre-formed plasmas. Topics covered will include Laser-driven XRLs, Collisional XRLs, Recombination XRLs, Transient Inversion Collisional XRLs, Optical Field Ionization XRLs, Alternative XRL, pumping schemes Theory and simulations of XRL gain media and beam properties High order harmonic sources of XUV radiation, Free-electron lasers and other accelerator based X-Ray sources, X-Ray Laser drives, X-Ray optics and instrumentation Spectroscopy, and other diagnostics of laser media Applications of XRLs.

Author: Alison Marie-Anne Saunders
Publisher:
ISBN:
Category :
Languages : en
Pages : 143

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High energy density physics (HEDP) is an emerging field that seeks to investigate the properties of matter at extreme conditions. High energy density conditions occur in materials with pressures exceeding 1 Mbar, or pressures that exceed Earth’s atmospheric pressure by a factor of more than a million. A regime of HEDP of particular interest is warm dense matter (WDM) physics, which describes the behavior of materials at near solid densities and 10’s of eV temperatures. WDM occurs in astrophysical objects, such as giant planets and brown dwarfs, and is also generated in inertial confinement fusion (ICF) experiments. X-ray Thomson scattering (XRTS) offers a powerful tool to probe the equation of state of WDM. XRTS spectra consist of two components: elastically scattered photons with the frequency of the original x-ray source and inelastically scattered photons that are down- shifted in frequency. The Compton-shifted profile of inelastically scattered x-rays can be analyzed to return the sample’s electron density and electron temperature. The ratio of elastically to inelastically scattered x-rays relates to the number of tightly bound versus free electrons, and thus reflects the ionization state. This thesis discusses the results of XRTS experiments on WDM performed at the OMEGA Laser facility. The first experiment presents and discusses XRTS results from 1 mm diamond spheres. The scattering spectra show evidence of higher ionization than predicted by several commonly-applied ionization models. A second experiment analyzed the contributions to elastic scattering from a small argon impurity in imploding beryllium capsules. The exper- iment found that less than 1 at.% of argon significantly affects the elastic scattering signal strength, and concluded that impurities in a sample should be considered before drawing conclusions from elastic scattering signals. The final experiment uses XRTS to measure the electron temperature and ionization state in isochorically heated materials used in ion stopping power experiments. The results from these experiments demonstrate the power of XRTS to measure ionization in WDM to benchmark theoretical modeling.

Author: Ernst Fill
Publisher: CRC Press
ISBN: 9780854984152
Category : Technology & Engineering
Languages : en
Pages : 486

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X-Ray Lasers 1992 contains a total of 92 papers from many of the world's leading researchers in the rapidly developing field of x-ray lasers. The book accurately reflects trends in x-ray laser research, particularly in pump mechanisms other than collisional pumping. It also focuses on the realization of new ideas for generating inversions at x-ray transitions.