Influence of binary particle collisions on trapped particle nonlinearities and the onset of stimulated Raman backscatter in the kinetic regime
POSTER
Abstract
The onset of stimulated Raman backscatter (SRBS) in a single laser speckle is examined in the kinetic regime using 1D and 2D VPIC [K. J. Bowers et \textit{al}., Phys. Plasmas \textbf{15}, 055702] simulations. A binary particle collision model [T. Takizuka and H. Abe, J. Comput. Phys. \textbf{25}, 205] is used to isolate and independently study the effects of like-particle (e-e) and pair-particle (e-i) collisions on trapped particle nonlinearities (e.g., frequency shift) in relation to SRBS onset, under conditions relevant to short-pulse ($\sim$3 ps at FWHM), single-speckle experiments at Trident [J. L. Kline et \textit{al}., J. Phys.: Conf. Series \textbf{112}, 022042]. Regimes of weak and strong collisionality are identified and collisional results are compared with those obtained in the collisionless limit [L. Yin et \textit{al}., J. Phys.: Conf. Ser. \textbf{112}, 022033].
*This work was performed under the auspices of the US DOE.