Abstract: In the inner magnetosphere, the magnetosonic waves have been proposed to transit-time scatter the radiation belt electrons over a broad range of energy and pitch-angle. Recent observations have shown that magnetosonic waves can be generated in the off-equatorial plasmasphere, whose latitudinal coverage and propagation angle are significantly different from the traditional magnetosonic waves confined near the equator. Using our previously-developed test-particle code, we here investigate the possible transit-time scattering of radiation belt electrons by the off-equatorially generated magnetosonic waves. Our results indicate that the transit-time scattering is primarily related to the perturbation near the edge of the finite wave train. The extending of wave occurrence latitudes causes the shrinking of the equatorial pitch-angle range of the transit-time scattering. Compared to the near-equatorially confined magnetosonic waves, the off-equatorially generated magnetosonic waves produce ignorable pitch-angle perturbations but slightly stronger energy perturbations.

Key words: magnetosonic wave, radiation belt, transit-time scattering