Influence of magnetospheric convection and polar wind on loss of electrons from the outer radiation belt

It is suggested that the principal loss of energetic electrons from the outer Van Allen belt occurs in the morning hours from violation of the quasi-stable trapping limit. During disturbed times when the maximum loss occurs in the early morning hours, acceleration of the particles by the convective electric field produces the violation of the stable limit. During less disturbed times the maximum precipitation is in the late morning hours and is caused by cold plasma flow from the ionosphere into the magnetosphere, which increases the equatorial plasma density and decreases the magnetic energy density per particle. This reduces the particle threshold energy for the whistler mode instability, thus causing previously large fluxes of lower energy electrons to become subject to the trapping limit.