Ion injections at auroral latitude during the March 31, 2001 magnetic storm observed by Cluster

Abstract

We present here simultaneous H+ and O+ ion dispersion signatures observed by three Cluster spacecraft above the northern auroral zone. These observations occur during strong geomagnetic activity (Kp = 9) and are consistent with a time-of-flight (TOF) dispersion of the ions. Using the TOF dispersion of H+ and O+ and bouncing properties of H +, we show that the ions originate from a distant source located near 80 Re down tail. Our results show that the magnetotail is topographically stable to support multiple bouncing of H+ ions during a storm period. Furthermore these results could suggest that the plasmasheet H+ and O+ ions have been accelerated to the same velocity in the vicinity of a reconnection region. Copyright 2004 by the American Geophysical Union.