Bounce resonance diffusion coefficients for spatially confined waves

Theoretical bounce resonance diffusion coefficients from interactions between electrons and spatially confined waves are derived and validated. Roberts and Schulz bounce resonance diffusion coefficients assume waves to be present on the whole bounce trajectory of particles; therefore, they are not directly applicable to waves that have a finite spatial extent. We theoretically derive and numerically validate a new set of bounce resonance diffusion coefficients for spatially confined waves. We apply our analysis to magnetosonic waves, which are confined to equatorial regions, using a previously published magnetosonic wave model. We find that the bounce resonance diffusion coefficients are comparable to the gyroresonance diffusion coefficients. We conclude that bounce resonance diffusion with magnetosonic waves might play an important role in relativistic electron dynamics.