Geoeffectiveness of Transient Ion Foreshock Phenomenon

Abstract:

We present results of an investigation on which Transient Ion Foreshock Phenomenon (HFAs, SHFAs, Foreshock Bubbles, etc.) produce the largest signatures observed by ground-based magnetometer networks, and thus are most “geoeffective.” The analysis follows two separate paths: We first assessed published lists of various foreshock transients (observed by spacecraft), both event-based and statistical studies, for associated ground signatures using an automated detection algorithm. We then reversed the search direction, starting with ground-based magnetometer records, for all THEMIS dayside passes. Initial results indicate that many large, “geoeffective,” events are in fact related to foreshock transients, but these events are not always captured in typical identification schemes applied to spacecraft data.