First medium energy neutral atom (MENA) images of Earth's magnetosphere during substorm and storm-time

Initial ENA images obtained with the MENA imager on the IMAGE observatory s how that ENAs emanating from Earth's magnetosphere at least crudely track b oth Dst and Kp. Images obtained during the storm of August 12, 2000, clearl y show strong ring current asymmetry during storm main phase and early reco very phase, and a high degree of symmetry during the late recovery phase. T hus, these images establish the existence of both partial and complete ring currents during the same storm. Further, they suggest that ring current lo ss through the day side magnetopause dominates other loss processes during storm main phase and early recovery phase.