Modelling neutral beam injection (NBI) in fusion reactors requires computing the trajectories of large ensembles of particles. Slowing down times of up to one second combined with nanosecond time steps make these simulations computationally very costly. This paper explores the performance of BGSDC, a new numerical time stepping method, for tracking ions generated by NBI in the DIII-D and JET reactors. BGSDC is a high-order generalization of the Boris method, combining it with spectral deferred corrections and the Generalized Minimal Residual method GMRES. Without collision modelling, where numerical drift can be quantified accurately, we find that BGSDC can deliver higher quality particle distributions than the standard Boris integrator at comparable computational cost or comparable distributions at lower computational cost. With collision models, quantifying accuracy is difficult but we show that BGSDC produces stable distributions at larger time steps than Boris.

在聚变反应堆中对中性束注入（NBI）进行建模需要计算大颗粒粒子的轨迹。高达一秒的减速时间与纳秒级的时间步长相结合，使这些模拟的计算成本非常高。本文探索了一种新的数值时间步长方法BGSDC的性能，该方法可跟踪NBI在DIII-D和JET反应器中产生的离子。BGSDC是Boris方法的高阶推广，结合了光谱延迟校正和广义最小残差方法GMRES。在没有碰撞建模的情况下，可以精确地量化数值漂移，我们发现BGSDC可以以可比的计算成本或标准的以较低的计算成本提供比标准Boris积分器更高质量的粒子分布。对于碰撞模型，