Investigation of Ring Current Response to CIR-Driven Geomagnetic Storms.

摘要

The physics of ring current behavior during Coronal Mass Ejection (CME)-driven storms is well understood and can be modeled with moderate accuracy. The effects of Corotating Interaction Region (CIR)-driven storms are less understood and tend to not agree with expected values.;Various approaches are employed to examine the differences in ring current behavior during storms driven by these two types of events. Satellite data (Polar CAM-MICE/MICS) are analyzed to determine differences in pitch angle distributions and energy densities, in order to provide insight into how the various ring current enhancement and loss processes differ during the different types of events. A ring current model (the Comprehensive Ring Current Model) is also employed to analyze these differences by modeling ring current behavior during CME and CIR events that fit a typical solar wind profile.;No differences in convection were noted in satellite data during CME and CIR-driven storms of similar strength, although oxygen was found to contribute more to the energy density during CIRs. However, model results demonstrated that there is a significant difference in ring current response during storms associated with the different drivers. It was determined that particle convection appears to be the primary ring current energization mechanism for CME-driven events, while other factors seem to influence the induced surface magnetic disturbance during CIR-driven storms; possibly boundary conditions, external currents or fluctuations caused by the associated wave-induced oscillations in the solar wind.