超强激光照射三维时变等离子体散射新机制

A new mechanism on scattering of 3D time-varying plasma

应用多光子非线性Compton散射模型和电流密度拉普拉斯变换改进的时域有限差分法,研究了超强激光照射三维时变等离子体的散射特性,提出了Compton散射光是影响等离子体散射的新机制,给出了该等离子体散射截面和频率随时间变化的修正方程,并进行了数值仿真.结果表明:与Compton散射前相比,Compton散射使等离子体散射截面增大,且随频率增大迅速衰减.这是因散射使等离子体中电子从耦合激光场中获得更多能量,从而导致电子被耦合场俘获的缘故;使瞬变等离子体最大频率随时间呈准直线缓慢下降趋势.这是因散射使等离子体中电子辐射阻尼效应增强,从而导致电子能量衰减、频率下降的缘故;使缓变等离子体频率随时间缓慢增大.这是因散射使等离子体中电子辐射阻尼增大效应减弱了频率增大的缘故.

By using the model of the multi -photon nonlinear Compton scattering and a modified means of Laplace transform finite-difference time-domain（LTJEC-FDTD） ,the influences of the characteristics of electromagnetic scattering on the 3D time-varying plasma under the extra-intensity laser illuminating are studied ,a new mechanism on plasma scattering of the influence produced by Compton scattering is given ,the amending equations on the scattering section of the plasma and frequency change with time have been given out ,and the equations are simulated with numbers .The results show that the scattering section of the plasma is increased by Compton scattering than that before Compton scattering ,and the increasing of the plasma frequency is quickly decreased .The cause is that the big energy from the cou-pling laser field is get by electron in the plasma under Compton scattering ,therefore the electron is cap-tured by the coupling laser field ;The maximum frequency of the instantaneous change plasma is slowly decreased with quasi -rectilinear form by Compton scattering ,and the cause is that the radiation damp-ing effects of the electron in the plasma are increased by Compton scattering ,therefore the energy and frequency of the electron are decreased ;The frequency of the slow changing plasma is slowly increased with time change by Compton scattering ,and the cause is that the frequency increasing effect is de-creased by the increasing effect of the radiation damping of the electron in the plasma .