Download or read book Suprathermal Electron Transport in Laser produced Plasmas written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-consistent, collisional, particle-in-cell scheme has been developed to model the one dimensional transport of suprathermal electrons in laser produced plasmas. This full Monte Carlo approach was taken, since earlier, simpler models have failed to explain an experimentally almost universal anomalous inhibition of thermal transport. The Monte Carlo scheme allows for free-streaming, ion scatter, and self thermalization of the electrons, which are moved in self-consistent E-fields computed with the aid of implicit fluid moments. PIC hydrodynamics for the ions, ponderomotive forces, and resonance and inverse-bremsstrahlung absorption of the light are all accommodated. In application to the anomalous inhibition problem, use of the scheme demonstrates that intrinsic differences in the Monte Carlo, and conventional flux-limited diffusion modelling of the transport results in apparent and real inhibition, explaining the need for strong flux-limiting in the simpler diffusion modelling of experiments.
Download or read book Numerical Modeling of Suprathermal Electron Transport in Laser produced Plasmas Report Number 36 written by and published by . This book was released on 1976 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supra-thermal electrons can radically alter the dynamics of imploding laser fusion targets by preheating the target material, by transforming energy to a rapid ion blowoff or, due to mean free path effects, decoupling the core from the corona. In order to correctly simulate the dynamics of a laser driven target, it is necessary to develop an accurate physical and computational model of these electrons. The difficulties inherent in this problem can be appreciated by noting that the supra-thermal velocities can vary by over an order of magnitude while the density of the background thermal electron fluid through which they propagate can vary by over four orders of magnitude. Since the supra-thermal mean free-path is proportional to v4/n{sub e}, there can be an eight order of magnitude variation in this scaling parameter. Since the transport of supra-thermal electrons must be followed in both the diffusive and free streaming limits, neither flux limited diffusion models nor truncated moment methods are adequate. A three component model of transport of supra-thermal electrons is developed here to satisfy all requirements discussed in this paper.
Download or read book Evidence for a Hot electron Flux Limit in Laser produced Plasma Experiments written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been found that it is necessary to impose a flux limit on the thermal electron transport in diffusion calculations of laser-produced plasmas to explain the observed partition of energy into fast and slow ions and x-rays. The effect of such a limit is to retain the deposited energy in the corona of the target. This containment increases the energy loss to fast ions, reduces the x-ray emission, and reduces the hydrodynamic efficiency. Although calculations for plasmas produced by lasers having wavelengths of 1 .mu.m or shorter agree with experiment when a flux limit which is 1/30 times the classical flux limit is applied to the electron thermal flux, I will show that such a flux limit cannot explain the results obtained for 10 .mu.m lasers. In this case it will be shown necessary to invoke a flux limit on the hot or suprathermal electrons.
Download or read book Test of Models for Electron Transport in Laser Produced Plasmas written by and published by . This book was released on 2005 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper examines five different models of electron thermal transport in laser produced spherical implosions. These are classical, classical with a flux limit f, delocalization, beam deposition model, and Fokker-Planck solutions. In small targets, the results are strongly dependent of f for flux limit models, with small f's generating very steep temperature gradients. Delocalization models are characterized by large preheat in the center of the target. The beam deposition model agrees reasonably well with the Fokker-Planck simulation results. For large, high gain fusion targets, the delocalization model shows the gain substantially reduced by the preheat. However flux limitation models show gain largely independent of f, with the beam deposition model also showing the same high gain.
Download or read book Atoms Solids and Plasmas in Super Intense Laser Fields written by Dimitri Batani and published by Springer Science & Business Media. This book was released on 2001-09-30 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 30th Course of the International School of Quantum Electronics on Atoms, Solids and Plasmas in Super-Intense Laser Fields, held 8-14 July, in Erice, Sicily
Download or read book Suprathermal Electrons in KJ laser Produced Plasmas M Shell Resolved High resolution X ray Spectroscopic Study of Transient Matter Evolution written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Electron Transport in Short Pulse Laser Produced Plasmas written by and published by . This book was released on 1997 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Transport Ion Acoustic Dynamics in Laser produced Plasmas written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis laser-plasma processes are studied at transport and ion time scales. In order to study these processes the particle-in-cell code QNPIC with one spatial dimension and three dimensions in velocity space was developed. Collisional effects are included by a Monte Carlo procedure, and an electric field solver based on the quasineutrality condition has been implemented. This allows long time scale simulations without having to resolve the electron plasma frequency. Collisional heating of the electrons in the laser electric field is one of the major restrictions on the time step in particle-in-cell codes. We have developed a collisional heating procedure that is based on a Langevin equation. It utilizes a Fokker-Planck equation that describes heating time averaged over the laser frequency. This procedure, in conjunction with the fast field solver and procedures to represent collisions, allows simulation of long time scale in laser-plasma interactions without the need to resolve the short time scales to ensure numerical stability and suppress numerical artifacts. We have studied in detail homogeneously heated plasmas and the effects of electron-electron collisions and collisional heating on the electron distribution function. We have suggested a nonlocal, nonlinear heat transport model based on a earlier self consistent nonlocal transport theory that is formally restricted to small (linearized) temperature perturbations. Our model extends this model to the case of finite temperature perturbations. The model is tested successfully in simulations of hot spot relaxation of an initial temperature distribution that corresponds to the instantaneous release of heat into a spatially Gaussian temperature profile and Maxwellian velocity distributions of the electrons. In simulations of collisionally heated hot spots we qualitatively describe the effects of non-Maxwellian velocity distributions on the heat flux and the change of the distribution function due to transpor.
Download or read book Numerical simulations of suprathermal electron ionisation dynamics and spectral line radiation transfer in short pulse laser produced plasmas written by Asif Khan and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Electron Transport in Overdense Laser induced Plasmas written by Jeremy Martin Hill and published by . This book was released on 2003 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fusion Energy Update written by and published by . This book was released on 1982-04 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Interaction of High Power Lasers with Plasmas written by Shalom Eliezer and published by CRC Press. This book was released on 2002-08-16 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Interaction of High-Power Lasers with Plasmas provides a thorough self-contained discussion of the physical processes occurring in laser-plasma interactions, including a detailed review of the relevant plasma and laser physics. The book analyzes laser absorption and propagation, electron transport, and the relevant plasma waves in detail. It al
Download or read book Self consistent Electron Transport in Collisional Plasmas written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-consistent scheme has been developed to model electron transport in evolving plasmas of arbitrary classical collisionality. The electrons and ions are treated as either multiple donor-cell fluids, or collisional particles-in-cell. Particle suprathermal electrons scatter off ions, and drag against fluid background thermal electrons. The background electrons undergo ion friction, thermal coupling, and bremsstrahlung. The components move in self-consistent advanced E-fields, obtained by the Implicit Moment Method, which permits .delta.t” .omega./sub p/−1 and .delta.x” lambda/sub D/ - offering a 102 - 103-fold speed-up over older explicit techniques. The fluid description for the background plasma components permits the modeling of transport in systems spanning more than a 107-fold change in density, and encompassing contiguous collisional and collisionless regions. Results are presented from application of the scheme to the modeling of CO2 laser-generated suprathermal electron transport in expanding thin foils, and in multi-foil target configurations.
Download or read book Suprathermal electron Generation Transport and Deposition in CO2 laser irradiated Targets written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments on both axial and lateral energy transport and deposition in spherical targets are described. A variety of diagnostics have been used to measure hot-electron transport and deposition including bremsstrahlung and inner-shell radiation and soft x-ray temperature measurements. Self-generated electric and magnetic fields play an important role in the transport and deposition of the hot electrons. In some cases distinct patterns of surface deposition consistent with magnetic-field configurations have been observed.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Transport Ion Acoustic Dynamics in Laser produced Plasmas written by Frank Detering and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser Plasma Interactions 5 written by M. B. Hooper and published by CRC Press. This book was released on 2019-10-01 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a broad overview in the increasingly important field of laser-plasma interactions. With the growth of research into fusion much international effort is being devoted to the problems of inertial confinement. This collection of lectures provides the novice researcher with the context in which current research papers can be understood. Laser Plasma Interactions 5 is one of the first publications to include recently declassified results from the United States inertial confinement fusion research program and as such is an indispensable reference for those wishing to find out about this previously inaccessible research. Presented by 14 speakers of international repute, the emphasis throughout the volume is on inertial confinement fusion. Topics also covered include plasma radiation and transport processes, diagnostic measurements, dense plasmas, high power lasers and X-ray lasers.
