Radiation belt diffusion via non-resonant interactions with spatially confined magnetosonic waves

Fast magnetosonic (MS) waves have the potential to affect radiation belt dynamics by scattering resonant energetic electrons. MS waves are typically found both inside and outside the plasmapause within ~2°-3° of the geomagnetic equator.They exhibit a near-perpendicular angle between the ambient magnetic field and the k-vector, which leads to near-equatorial confinement of wave power. Given this spatial confinement of MS waves, electrons can traverse the entire wavefield experiencing only a fraction of a wavelength. Test particle simulations have shown that this can lead to appreciable scattering in energy even in the absence of resonant interactions. The effects of this process on radiation belt dynamics, however, are still unclear. By using numerical methods for solving the diffusion equation with diffusion coefficients computed from linear theory, we attempt to elucidate these effects.