Analysis of stimulated Raman backscatter and stimulated Brillouin backscatter in experiments performed on SG-III prototype facility with a spectral analysis code

Abstract

Experiments about the observations of stimulated Raman backscatter (SRS) and stimulated Brillouin backscatter (SBS) in Hohlraum were performed on Shenguang-III (SG-III) prototype facility for the first time in 2011. In this paper, relevant experimental results are analyzed for the first time with a one-dimension spectral analysis code, which is developed to study the coexistent process of SRS and SBS in Hohlraum plasma condition. Spectral features of the backscattered light are discussed with different plasma parameters. In the case of empty Hohlraum experiments, simulation results indicate that SBS, which grows fast at the energy deposition region near the Hohlraum wall, is the dominant instability process. The time resolved spectra of SRS and SBS are numerically obtained, which agree with the experimental observations. For the gas-filled Hohlraum experiments, simulation results show that SBS grows fastest in Au plasma and amplifies convectively in C5H12 gas, whereas SRS mainly grows in the high density region of the C5H12 gas. Gain spectra and the spectra of backscattered light are simulated along the ray path, which clearly show the location where the intensity of scattered light with a certain wavelength increases. This work is helpful to comprehend the observed spectral features of SRS and SBS. The experiments and relevant analysis provide references for the ignition target design in future.

Study of crossed-beam energy transfer process with large crossing angle in three-dimension

“…Our simulation indicate that CBET process with large crossing angle has certain chance to occur under the complicated hohlraum plasma conditions, and might be very important because of its potential to induce other LPI instabilities and destroy the spatio-temporal symmetry. Besides, our model can also be expanded to multi-beams cases, and our simulation method establishes a basic for analysis of future multi-beams experiments on the Shenguang series facilities Hao et al, 2014;Huo et al, 2014) and provides valuable references for the intending ignition target design.…”

Summary of laser plasma physics sessions at the first AAPPS-DPP conference

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Laser plasma instability in indirect-drive inertial confinement fusion

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