Role of periodic loading‐unloading in the magnetotail versus interplanetary magnetic field Bz flipping in the ring current buildup

Abstract

Introducing kinetic corrections into the to BATSRUS code in the magnetotail region leads to fast reconnection rates observed in kinetic simulations and quasi‐periodic loading‐unloading cycles in the magnetotail during a long period of steady southward interplanetary magnetic field (IMF) Bz (Kuznetsova et al., 2006, 2007). We use the global MHD code BATSRUS output to drive the Fok Ring Current (FRC) model, which then exhibits quasi‐periodic oscillations of geosynchronous energetic particle fluxes, similar to “sawtooth” injection profiles. We compare these results with the results of the FRC model driven by BATSRUS for periodically flipping IMF Bz component, without kinetic corrections. The comparison shows the dominant role of quasi‐periodic loading‐unloading in the tail over the role of flipping IMF Bz component in the formation of geosynchronous fluxes for various energies. This same result is confirmed by the analysis of particle number and energy content within geosynchronous orbit.