Theory and simulations of relativistic particle motions in a magnetosonic shock wave

摘要

The motions of relativistic particles in a magnetosonic shock wave propagating obliquely to an external magnetic field are studied. In the zeroth-order theory, particles continue to move nearly parallel to the external magnetic field in the shock transition region, when the shock speed is close to c cos theta, where c is the speed of light and theta is the propagation angle. Perturbations to this zeroth-order motion are also analyzed for positrons and ions. The perturbation frequency of positrons is omega similar to Omega(po)gamma(-1) and that of ions is omega similar to Omega(io)gamma(-1/2), where Omega(po) and Omega(io) are the non-relativistic gyrofrequencies of positrons and of ions, respectively, and gamma is the Lorentz factor. These theoretical predictions are confirmed with numerical simulations.