Bounce Resonance between Energetic Electrons and Magnetosonic Waves: A
Parametric Study
Abstract
Magnetosonic waves are electromagnetic emissions from a few to 100 Hz
primarily confined near the magnetic equator both inside and outside the
plasmasphere.
Previous studies proved that MS waves can transport equatorially
mirroring electrons from an equatorial pitch angle of
90$^\circ$ down to lower values by bounce
resonance.
But the dependence of bounce resonance effect on wave or background
plasma parameters is still unclear.
Here we applied a test particle simulation to investigate electron
transport coefficients, including diffusion and advection coefficients
in energy and pitch angle, due to bounce resonance with MS waves.
We investigate five wave field parameters, including wave frequency
width, wave center frequency, latitudinal distribution width, wave
normal angle and root-mean-square of wave magnetic amplitude, and two
background parameters, $L$-shell value and plasma density.
We find different transport coefficients peaks resulted by different
bounce resonance harmonics. Higher order harmonic resonances exist, but
the effect of fundamental resonance is much stronger. As the wave center
frequency increases, higher order harmonics start to dominate. With wave
frequency width increasing, the energy range of effective bounce
resonance broadens, but the effect itself weakens.
The bounce resonance effect will increase when we decrease the wave
normal angle, or increase the wave amplitude, latitudinal distribution
width, L-shell value, and plasma density.
The parametric study will advance our understanding of the favorable
conditions of bounce resonance.