论文标题
使用粒子中的粒子算法对相对论粒子激光相互作用进行建模的新现场求解器
A new field solver for modeling of relativistic particle-laser interactions using the particle-in-cell algorithm
论文作者
论文摘要
提出了一种定制的有限差分差异范围求解器（PIC）算法，该算法提供了更高的电磁波中波颗粒相互作用的保真度。在许多感兴趣的问题中，具有相对论能量的颗粒与强烈的电磁场相互作用，这些电磁场的速度接近光速。由于（1）波速度的分散误差，可能会出现数值误差，（2）电场和磁场之间以及粒子速度和位置之间的时间差异，在动量进步中的时间导数中的粒子速度和（3）误差。详细分析了前两种错误的错误。结果表明，通过在法拉第和安培定律中使用具有不同$ \ mathbf {k} $ - 太空运营商的场求解器，可以同时删除粒子推动器中的分散误差和磁场及时的误差，以用于主要沿特定方向移动的电磁波。新算法是通过使用自定义的高阶有限差分运算符将新算法实施的。通过PIC模拟比较了使用所提出的求解器与不同粒子推器结合使用的方案。结果表明，新算法的使用以及分析粒子推动器（假设在一个时间步长的恒定字段）可以导致在具有归一化矢量电位的强激光场中的单个电子运动的准确建模，$ ea/mc^2 $，超过$ 10^4 $，超过了$ 10^4 $的典型单元格和时间步骤。
A customized finite-difference field solver for the particle-in-cell (PIC) algorithm that provides higher fidelity for wave-particle interactions in intense electromagnetic waves is presented. In many problems of interest, particles with relativistic energies interact with intense electromagnetic fields that have phase velocities near the speed of light. Numerical errors can arise due to (1) dispersion errors in the phase velocity of the wave, (2) the staggering in time between the electric and magnetic fields and between particle velocity and position and (3) errors in the time derivative in the momentum advance. Errors of the first two kinds are analyzed in detail. It is shown that by using field solvers with different $\mathbf{k}$-space operators in Faraday's and Ampere's law, the dispersion errors and magnetic field time-staggering errors in the particle pusher can be simultaneously removed for electromagnetic waves moving primarily in a specific direction. The new algorithm was implemented into OSIRIS by using customized higher-order finite-difference operators. Schemes using the proposed solver in combination with different particle pushers are compared through PIC simulation. It is shown that the use of the new algorithm, together with an analytic particle pusher (assuming constant fields over a time step), can lead to accurate modeling of the motion of a single electron in an intense laser field with normalized vector potentials, $eA/mc^2$, exceeding $10^4$ for typical cell sizes and time steps.
