1Strong stretching in dusk sector: stormtime activations and sawtooth events compared

Abstract: Using superposed epoch analysis methods, we analyze two sets of events: one of stormtime activations having some characteristics of sawtooth events, and another set of events defined as sawtooth events. We compare and contrast these data sets and show that the sawtooth events are associated with slightly lower than average solar wind driving but the differences are small. While the both sets of events are associated with a positive excursion of the SYM-H index, the stormtime activations show a clearer signal in the ASY-H index highlighting the role of the partial ring current in such events. In the inner magnetotail, both sets of events show qualitatively similar injection and field dipolarization characteristics. We conclude that the repetition period of the sawtooth events is an internal property of the magnetosphere not related to the particular driving conditions that prevail during the sawtooth events. Key words: stormtime substorms, sawtooth events. 1