周期量级超短激光脉冲在近临界密度等离子体中形成的光孤子

利用一维粒子模拟程序，观测到周期量级的超短激光脉冲在等离子体中可以以孤子形式传播.它在一定密度等离子体中以较高的群速度向前传播，并在到达等离子体与真空界面时发生反射和透射.当入射激光脉冲强度增大时，非线性调制效应使它产生较大的频率下移，致使光孤子传播速度变小.另外，对于同样光强下的几十个周期以上的光脉冲，它在等离子体中传播时形成的则是一连串低频的被捕获在等离子体中的光孤子. 关键词： 光孤子 超短激光脉冲 等离子体 粒子模拟

Solitons formed by ultrashort laser pulses propagating in a plasma

Using one-dimensional particle-in-cell simulations, we observed the formation of solitons which can move with high group velocities when ultrashort laser pulses at a few cycles only propagate in underdense plasma near the critical density. There exist reflection and transmission when the solitons arrive at the plasma-vacuum boundary. When the intensity of initial laser pulses increases, the velocity of the formed solitons decreases. When a laser pulse at a few tens of cycles propagates in such a plasma, a cluster of solitons are left behind, and trapped in the plasma.