Orbit Averaging and Subcycling in Particle Simulation of Plasmas

Publisher Summary Plasma physics phenomena occur over an enormous range of space and time scales. The motion of charged particles in inhomogeneous and time varying electric and magnetic fields with collisions and collective effects is very complicated. Plasma contains a multitude of distinct time and space scales that span many orders of magnitude. An example is illustrated with a range of four orders of magnitude in spatial scales and a range of 6–12 orders of magnitude in time scales. This makes realistic simulation of time-dependent plasma phenomena generally very difficult. This chapter presents the particle simulation methods to resolve disparate time scales. These methods complement the implicit particle simulation methods described—the implicit moment method and the direct implicit method. The chapter also discusses two multiple-timescale methods that are electron subcycling and orbit averaging. Both achieve significant gains in efficiency over traditional particle simulation approaches for appropriate applications.