Acceleration of relativistic electrons via drift-resonant interaction withtoroidal-mode Pc5 ULF oscillations

There has been increasing evidence that Pc-5 ULF oscillations play a fundam ental role in the dynamics of outer zone electrons. In this work we examine the adiabatic response of electrons to toroidal-mode Pc-5 field line reson ances using a simplified magnetic field modal. We find that electrons can b e adiabatically accelerated through a drift-resonant interaction with the w aves, and present expressions describing the resonance condition and half-w idth for resonant interaction. The presence of magnetospheric convection el ectric fields is seen to increase the rate of resonant energization, and al low bulk acceleration of radiation belt electrons. Conditions leading to th e greatest rate of acceleration in the proposed mechanism, a nonaxisymmetri c magnetic field, superimposed toroidal oscillations, and strong convection electric fields, are likely to prevail during storms associated with high solar wind speeds.