冲击点火高强度激光作用下长密度标度长度等离子体中的泵浦耗尽与热电子产生

Pump depletion and hot-electron generation in long-density-scale-length plasma with shock-ignition high-intensity laser.

作者信息

Li J, Zhang S, Krauland C M, Wen H, Beg F N, Ren C, Wei M S

机构信息

Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA.

Inertial Fusion Technology, General Atomics, San Diego, California 92121, USA.

出版信息

Phys Rev E. 2020 Mar;101(3-1):033206. doi: 10.1103/PhysRevE.101.033206.

DOI:10.1103/PhysRevE.101.033206

PMID:32289963

Abstract

Two-dimensional particle-in-cell simulations for laser plasma interaction with laser intensity of 10^{16}W/cm^{2}, plasma density range of 0.01-0.28n_{c}, and scale length of 230-330μm showed significant pump depletion of the laser energy due to stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in the low-density region (n_{e}=0.01-0.2n_{c}). The simulations identified hot electrons generated by SRS in the low-density region with moderate energy and by two-plasmon-decay near n_{e}=0.25n_{c} with higher energy. The overall hot electron temperature (46 keV) and conversion efficiency (3%) were consistent with the experiment's measurements. The simulations also showed artificially reducing SBS would lead to stronger SRS and a softer hot-electron spectrum.

摘要

二维粒子模拟显示，在激光强度为10^{16}W/cm^{2}、等离子体密度范围为0.01-0.28n_{c}以及尺度长度为230-330μm的激光等离子体相互作用中，由于低密度区域（n_{e}=0.01-0.2n_{c}）中的受激拉曼散射（SRS）和受激布里渊散射（SBS），激光能量出现了显著的泵浦耗尽。模拟确定了在低密度区域由SRS产生的具有中等能量的热电子，以及在n_{e}=0.25n_{c}附近由双等离子体衰变产生的具有较高能量的热电子。总的热电子温度（46 keV）和转换效率（3%）与实验测量结果一致。模拟还表明，人为降低SBS会导致更强的SRS和更软的热电子能谱。