Suppression of stimulated Brillouin scattering in laser beam hot spots
Suppression of stimulated Brillouin scattering in laser beam hot spots
复制标题
DOI：
10.1017/s026303460999036x
复制
发表时间：
2009-12
影响因子：
0.9
通讯作者：
R. Sharma;P. Sharma;S. Rajput;A. Bhardwaj
中科院分区：
文献类型：
--
作者：
R. Sharma;P. Sharma;S. Rajput;A. Bhardwaj
本文研究了考虑有质动力非线性的强激光束在热的无碰撞等离子体中的传播。研究了激光束自聚焦对离子声波局域化和受激布里渊散射过程的影响。激光束与IAW之间的非线性耦合导致IAW的本征频率发生改变，从而导致IAW的朗道阻尼增强和SBS过程中失配因子的改变。由于朗道阻尼的增强，IAW波的强度降低，SBS过程得到抑制。当激光功率密度为<$1016W/cm 2，激光束半径（r 0）为<$12mm，n/ncr为<$0.11，（Te/Ti）为<$10时，SBS反射率被抑制了约10%.
In this article, filamentation of a high power laser beam in hot collisionless plasma is investigated considering the ponderomotive nonlinearity. We have studied the effect of self focusing (filamentation) of the laser beam on the localization of ion acoustic wave (IAW) and on stimulated Brillouin scattering (SBS) process. The nonlinear coupling between the laser beam and IAW results in the modification of the Eigen frequency of IAW; consequently, enhanced Landau damping of IAW and a modified mismatch factor in SBS process occur. Due to enhanced Landau damping, there is a reduction in the intensity of IAW wave, and the SBS process gets suppressed. For the typical laser plasma parameters: the laser power flux ¼ 10 16 W/cm 2 , laser beam radius (r0) ¼ 12 mm, n/ncr ¼ 0.11, and (Te/Ti) ¼ 10, the SBS reflectivity is found to be suppressed approximately by 10%.