The convergence of Boltzmann Fokker Planck solution can become arbitrarily slow with iterative procedures like source iteration. This paper derives and investigates a nonlinear diffusion acceleration scheme for the solution of the Boltzmann Fokker Planck equation in slab geometry. This method is a conventional high order low order scheme with a traditional diffusion-plus-drift low-order system. The method, however, differs from the earlier variants as the definition of the low order equation, which is adjusted according to the zeroth and first moments of the Boltzmann Fokker Planck equation. For the problems considered, we observe that the NDA-accelerated solution follows the unaccelerated well and provides roughly an order of magnitude savings in iteration count and runtime compared to source iteration.

翻译：玻尔兹曼-福克-普朗克方程解的收敛性在采用源迭代等迭代过程时可能变得任意缓慢。本文推导并研究了一种用于求解平板几何中玻尔兹曼-福克-普朗克方程的非线性扩散加速方案。该方法是一种传统的高阶-低阶格式，其低阶系统为经典的扩散加漂移形式。然而，该方法区别于早期变体的关键在于低阶方程的定义方式——该定义根据玻尔兹曼-福克-普朗克方程的零阶矩和一阶矩进行调整。对于所考虑的问题，我们观察到：经过NDA加速的解与未加速解吻合良好，且与源迭代相比，在迭代次数和运行时间上均节省了约一个数量级。