Sources of hot electrons in laser-plasma interaction with emphasis on Raman and turbulence absorption
Heating targets with high power lasers results in a sizable fraction of the absorbed energy going into electrons of temperature much greater than thermal which can pre-heat the pellet core and accelerate fast ion blowoff which results in poor momentum transfer and hence poor compression efficiency. The present emphasis is to build lasers of higher frequency, ..omega../sub 0/, which at the same W/cm/sup 2/ results in more absorption into cooler electrons. Two physical reasons are that the laser can propagate to a higher electron density, n, infinity..omega../sub 0//sup 2/ resulting in more collisional inverse bremsstrahlung absorption proportional to n, and because the hot temperatures from some plasma absorption processes increase as the oscillatory velocity of an electron in the laser electric field v/sub 0//c = eE/(m/sub e/..omega../sub 0/). The heated electron temperatures from other plasma processes (Raman for example approx.(m/sub e//2)v/sup 2//sub phase/ and the higher laser frequency helps by increasing the competing collisional absorption and decreasing the Raman gain.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5222660
- Report Number(s):
- UCRL-87496; CONF-820528-3; ON: DE82012787; TRN: 82-014640
- Resource Relation:
- Conference: US/Japan seminar on theory and application of multiple ionized plasmas produced by laser and particle beams, Nara, Japan, 2 May 1982; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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