激光等离子体相互作用中Weibel不稳定性

摘要

The paper studies Weibel instabilities in ultra intense laser-plasma interactions and its mechanism by using relati-vistic particle-in-cell method, and gives linear dispersion relations, saturated magnetic fields and anisotropy parameters of Weibel instabilities. It is found that the presence of Weibel instabilities in ultraintense laser-plasma interactions makes the self-generated magnetic field saturate, and then the saturated magnetic field causes the anisotropy of particle velocity distribution along the laser propagation direction. The linear and non-linear saturation processes of Weibel instabilities are also discussed. These results may be important for understanding the static magnetic field generation and fast electron propagation in the fast ignition physics.%利用粒子模拟法对超强激光与等离子体相互作用中产生的Weibel不稳定性及其产生机制进行了详细的研究.给出不稳定性的线性色散关系和饱和磁场与各向异性参数之间的函数关系,发现Weibel不稳定性的存在使超强激光在等离子体中激发的自生磁场饱和,饱和自生磁场的存在使粒子速度分布在激光传播方向上表现出各向异性.讨论了Weibel不稳定性的线性和非线性饱和过程,对更好地理解快点火物理中自生磁场的产生、快电子输运等过程有重要意义.