Superthermal electron production from hot underdense plasmas
作者:
Shridhar Aithal,
Pierre Lavigne,
Henri Pe´pin,
Tudor Wyatt Johnston,
Kent Estabrook,
期刊:
Physics of Fluids(00319171)
(AIP Available online 1987)
卷期:
Volume 30,
issue 12
页码: 3825-3831
ISSN:0031-9171
年代: 1987
DOI:10.1063/1.866420
出版商: AIP
数据来源: AIP
摘要:
Very‐high‐energy electrons of up to an energy of ∼2.3 MeV have been observed to be emitted from the hot underdense exploding thin foil plasmas created by 10.6 &mgr;m CO2laser radiation at intensity levels up to ∼4×1014W/cm2. As a supplement to the electron measurements the forward and backward scattered light components were also measured. Correlation of these measurements shows that either Raman scattering or the high‐temperature version of two‐plasmon decay or both, manifesting themselves near the quarter‐critical density region, are responsible for the production of a hot (Th∼135 keV) tail of electrons at least up to energies of 1 MeV. There are no indications that the Raman forward scattering (as distinct from Raman backward scattering) at lower densities plays any significant role. These experimental results are consistent with the results from a l 1/2 ‐dimensional particle‐in‐cell code simulation with a parabolic density profile resembling the experimental conditions. An apparent anomaly is discussed, which is that hot electrons are produced (both in experiments and simulations) at energies higher than the trapping value appropriate to electron plasma waves whose phase velocity is equal to the matching value (C/(3)1/2) at the turning point for the light of half the laser frequency.
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