An Analytic Boris Pusher for Plasma Simulation

TL;DR

This paper introduces a faster, nearly analytic Boris pusher for plasma simulation that simplifies calculations by assuming small changes in gamma, trading some accuracy for increased speed.

Contribution

A new analytic Boris pusher is derived, offering a faster alternative to existing methods by simplifying gamma calculations with minimal accuracy loss.

Findings

Nearly twice as fast as previous pushers

Simplifies gamma calculation assuming small changes

Trade-off between speed and accuracy discussed

Abstract

This paper discusses how to improve the Boris pusher used to advance relativistic charged particles in fixed electromagnetic fields. We first derive a simpler solution to a flaw previously discovered by others. We then derive a new analytic Boris pusher that is a minor modification to the original split-time scheme, except for the calculation of {\gamma}. This analytic pusher assumes that the change of {\gamma} during a particle advance is small. It is less accurate than the pusher derived by Fei Li et. al., but is nearly twice as fast. We will discuss when it is advantageous and when it is not.