DIRECT IMPLICIT LARGE TIME-STEP PARTICLE SIMULATION OF PLASMAS
DIRECT IMPLICIT LARGE TIME-STEP PARTICLE SIMULATION OF PLASMAS
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DOI：
10.1016/0021-9991(83)90083-9
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发表时间：
1983-01-01
影响因子：
4.1
通讯作者：
FRIEDMAN, A
中科院分区：
文献类型：
--
作者：
LANGDON, AB;COHEN, BI;FRIEDMAN, A
本文详细介绍了最近发展起来的一种隐式方法，用于求解粒子-场耦合方程组。这种隐式积分方案的动机是希望有效地研究低频，长波长等离子体现象，使用一个大的时间步长。特别地，该方法允许在不感兴趣电子等离子体振荡时使用大于电子等离子体周期的时间步长，并且提供对电子等离子体振荡的失真残余的选择性阻尼。这里提出的隐式格式直接使用粒子数据，而不引入流体矩方程作为场方程和粒子方程之间的中介。在静电场模型中，我们的方案的实质是在超前时刻将电荷密度关于一个显式近似密度线性化，并计算对在超前场中线性的电荷密度的增量修正。我们导致一个椭圆形的场方程，其系数直接依赖于粒子的数据积累在空间网格上的形式的有效线性磁化率。给出了隐式方程解的预测和迭代精化方法，以及方程的空间差分表示。描述了时间步长的剩余限制。它表明，收敛是上级时，空间差分和过滤是在一个一致的方式。
A recently developed implicit method for solving the set of coupled particle and field equations arising in particle-in-cell plasma simulation is described in detail. This implicit integration scheme is motivated by the desire to study efficiently low-frequency, long-wavelength plasma phenomena using a large time step. In particular, this method allows the use of a time step which is larger than the electron plasma period, when electron plasma oscillations are not of interest, and provides selective damping of the distorted remnant of the electron plasma oscillation. The implicit scheme presented here uses particle data directly without introducing fluid moment equations as an intermediary between the field and particle equations. In an electrostatic model, the essence of our scheme is a linearization of the charge density at the advanced time about an explicit approximate density and the computation of the incremental correction to the charge density that is linear in the advanced field. We are led to an elliptic field equation whose coefficients depend directly on particle data accumulated on the spatial grid in the form of an effective linear susceptibility. Prediction and iterative refinement of the solution of the implicit equations, and spatial difference representations of the equations are given. Residual restrictions on time step are described. It is demonstrated that convergence is superior when spatial diferencing and filtering are done in a consistent manner.