激光在等离子体中的坍塌行径

 从椭圆偏振激光场波包所满足的非线性控制方程出发，利用场论方法，构造该非线性方程的拉格朗日密度函数，得到激光场波包的能量集中具有准粒子特性，并给出守恒的粒子数、动量和能量。讨论了调制不稳定发展后期的波包坍塌动力学问题，利用归一化的粒子数密度分布作为权重，分析了激光场的波包。结果表明,激光场波包的尺度在有限的时间进程中，将塌缩到一个很小的值，证明了激光场具有塌缩行径。

Collapse behavior of laser beam in plasma

On the basis of the nonlinear equation for the wave packet of the elliptically polarized laser electric field, the Lagrange density function of the nonlinear equation is constructed by means of field theory. It is shown that the energy focus of the wave packet possesses the characteristic of quasi-particles. Moreover, the conserved quantities of plasmons, momentum, and energy are given. The collapse dynamics of the wave packet at the later stage of modulation instability is discussed. The normalized density distribution of the plasmon number is regarded as weight, and the wave packet of the laser electric field is analyzed. The result shows that the scale of the wave packet will collapse to a very small value in finite time, proving that the laser electric field possesses the collapsing be