Two-Dimensional Particle-In-Cell Simulation of Magnetosonic Wave Excitation in a Dipole Magnetic Field

The excitation of magnetosonic waves in the meridian plane of a rescaled dipole magnetic field is investigated, for the first time, using a general curvilinear particle-in-cell simulation. Our simulation demonstrates that the magnetosonic waves are excited near the equatorial plane by tenuous ring distribution protons. The waves propagate nearly perpendicularly to the background magnetic field along both radially inward and outward directions. Different speeds of inward and outward propagation result in the asymmetrical distribution about the source region. The waves are accompanied by energization of both cool protons and electrons near the wave source region. The cool protons are heated perpendicularly, while the cool electrons can be heated in the parallel direction and also experience enhanced perpendicular drift at the presence of intense wave power. The implications of simulation results to the observations of magnetosonic waves and related particle heating in the inner magnetosphere are also discussed. ©2018 American Geophysical Union. All Rights Reserved.