Ring current behaviour during corotating interaction region and high speed stream events

Abstract

The ring current behaviour during geomagnetic disturbances induced by Corotating Interaction Region (CIR) and High Speed Streams (HSS) in the solar wind is studied using particle data from low altitude polar orbiting satellites. The ion/proton precipitation during CIR/HSS events reveal the spatial and temporal dynamics of the ring current and plasma sheet during the events. Three CIR/HSS events and one Coronal Mass Ejection (CME) induced storm are studied. The invariant latitude of the low altitude equatorward boundary of isotropic proton precipitation is erratic and more noisy in the CIR/HSS events than in the CME storm. The boundary also varies more incoherently at the different local times during the CIR/HSS events. The estimated ion injection rates into the ring current are shown to increase mainly at L > 4 during CIR/HSS events. The production of Energetic Neutral Atoms (ENA) through charge exchange reactions in the ring current is also studied by the Storm Time Equatorial Belt (STEB) during CIR/HSS events. The STEB is found to exhibit low but above quiet-time levels of intensity.