激光等离子体不稳定性的入射光强度效应

Effect of Laser Intensity on Instability of Dense Plasma Irradiated by Ultra-Intense Laser-Plasma Interaction

用3维粒子模拟程序研究了相对论强激光和高密度等离子体相互作用引起的电磁不稳定。数值模拟表明,在线偏振强激光作用下,等离子体表面出现了电磁不稳定性。形成的不稳定结构随时间发展和激光功率密度的增加进一步深入到等离子体内部,最终使等离子体表面处激发饱和自生磁场。这种由电子速度各向异性而产生的自生磁场对激光有质动力推开电子时所形成的电子热流产生抑制作用,并将直接影响电子加速效率。

The surface instability of a dense plasma slab irradiated by a relativistic intense laser pulse is investigated using three-dimensional particle in-cell simulation. When the laser pulse is incident with p-polarization, electromagnetic instability is observed on the plasma surface. Later the instability propagates into the plasma bulk forming bubble structures, which propagate forward subsequently. The development of this instability depends upon the initial plasma density. The result of this research indicates that the strong magnetic field excited by instability makes the electron beam deposit the energy within very short distance. And, meanwhile, restrain the electron thermo current formed when the laser ponderomotive force burst through the electron.