Evidence for a Hot-electron Flux Limit in Laser-produced Plasma Experiments
Evidence for a Hot-electron Flux Limit in Laser-produced Plasma Experiments

Author:

Publisher:

Published: 1983

Total Pages:

ISBN-13:

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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.

Direct Measurements of Nonlocal Heat Flux in Laser-produced Coronal Plasmas Using Thomson Scattering from Electron-plasma Waves
Direct Measurements of Nonlocal Heat Flux in Laser-produced Coronal Plasmas Using Thomson Scattering from Electron-plasma Waves

Author: Robert James Henchen

Publisher:

Published: 2018

Total Pages: 155

ISBN-13:

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"Thermal transport is a fundamental process in plasma physics that is not well understood. Historically, local models have been used to describe the heat flux in plasmas but artificially limit the flux at even modest temperature gradients. This Thesis studies electron thermal transport in laser-produced coronal plasmas using a novel Thomson scattering technique. Thomson scattering is sensitive to changes in the electron distribution function caused by heat flux. The experiments show that nonlocal effects must be included in regions where the plasma was not collisional enough for classical theory to be valid. Vlasov-Fokker-Planck simulations self consistently calculated the electron distribution functions used to reproduce the measured Thomson scattering spectra and to determine the heat flux. Measured heat flux values were up to 40% smaller than classical values inferred from the measured plasma conditions in this region. This is the first direct measurement of nonlocal heat flux in plasmas. In the opposite limit, classical theory matched the observed Thomson scattering data. Multigroup nonlocal simulations overestimated the measured heat flux."--Page xi.

Laser Interaction and Related Plasma Phenomena
Laser Interaction and Related Plasma Phenomena

Author: Heinrich Hora

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 1145

ISBN-13: 1461573327

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This 6th International Workshop in the series starting in 1969 was held at the Naval Postgraduate School in Monterey, California from 25-29 October, 1982 under the continuing directorship of Heinrich Hora. The co-directorship of the late Helmut Schwarz who helped found the series was assumed by George Miley. Fred Schwirzke served as the local organizer. Following a commemoration for Helmut Schwarz, Heinrich Hora connnented that the long title of the workshop is originally due to Nicholas Bloembergen, who prophetically envisaged that "related plasma phenomena" such as is involved in particle beam fusion is also of enormous interest to the laser connnunity. The en thusiastic response of the workshop advisors and the 82 participants from 11 countries supports the need for a continuation of this work shop-type meeting where an innnediate discussion and documentation of new results and conceptual formulations occurs, a process not possible through the usual journals. The main sponsor of this year's confer ence was the Fusion Studies Laboratory of the University of Illinois. Thanks are also due to the Naval Postgraduate School, Monterey, and the Department of Theoretical Physics, University of New South Wales. The conference was made feasible by the contributions of the partici pants, and they and their institutions deserve many thanks. Special recognition is due to the Conference Secretary, Chris Stalker (Urbana), as well as to Marie Wesson (Sydney) and to Patricia Vardaro (Monterey).

Laser Interaction and Related Plasma Phenomena
Laser Interaction and Related Plasma Phenomena

Author: Helmut J. Schwarz

Publisher: Springer

Published: 1974-10-01

Total Pages: 578

ISBN-13: 9780306371509

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As was the case in the two preceding workshops of 1969 and 1971, the Third Workshop on "Laser Interaction and Related Plasma Phenomena" held in 1973 was of international character. The main purpose was to review the advanced status of this particular and turbulent field of physics as it had developed vigorously in all major laboratories of the world since 1971. Due to recently accelerated advancements, it was hardly possible to present a com plete tutorial review; the subject is still in its premature stages and changing rapidly. A topical conference would have been too specific for a group of physicists with broad backgrounds working in the field or for those just about to enter it. It was the aim of the workshop and it is the aim of these proceedings to help this large group of scientists find their way within the highly complex and sometimes confusing results of a new field. We optimized the task of the workshop with extensive reviews on several topics and at the same time included more detailed infor mation for specialists. The differences in their conclusions were not a matter of contention but rather served to complement the advanced results. As in the preceding workshops, we directed our attention toward critical realism in respect to the complexity of the field. What is meant here is exemplified in the contribution by R. Sigel ~.667).