Applying Thomson scattering to diagnosing turbulent density and velocity fluctuations in a gas-puff z-pinch
- Cornell Univ., Ithaca, NY (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Cornell Univ., Ithaca, NY (United States)
- Cornell Univ., Ithaca, NY (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
The electron plasma wave feature (EPW) in the time-resolved Thomson scattering spectrum is used to obtain the local electron density in imploding high energy density gas-puff z-pinch plasmas. The optical setup was optimized to allow the relatively weak EPW feature obtained from 1 MA imploding neon gas-puff z-pinches to be seen above the continuum emission as well as the brighter ion acoustic wave (IAW) feature. Using a frequency-doubled Nd:YLF laser (E = 10 J, λ = 526.5 nm, Δt= 2.3 ns, spot size ~ 250 μm) and two visible light streak cameras, we determined the average electron density in the imploding plasma sheath 40 ns prior to stagnation to be [Formula: see text]/cm3. At pinch time, it reached [Formula: see text]/cm3. The electron temperature during implosion measured via the IAW (approximately 50 eV) was four times lower than the implosion electron temperature measured via the EPW (approximately 200 eV), assuming that neither feature is affected by turbulent fluctuations in the plasma. In order for the electron temperatures inferred from the EPW and IAW spectral features to be self-consistent, we find that it is necessary to include velocity fluctuations in the analysis of the IAW feature peaks and corresponding density fluctuation in the peak widths of the EPW feature.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- NA0003764; AC52-07NA27344; B619181
- OSTI ID:
- 1899142
- Alternate ID(s):
- OSTI ID: 1898933; OSTI ID: 1905208
- Report Number(s):
- LLNL-JRNL-829499; TRN: US2310973
- Journal Information:
- Physics of Plasmas, Vol. 29, Issue 11; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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