Plasma sheet oscillations and their relation to substorm development: Cluster and double star TC1 case study
Zhang, T. L.; Klecker, B.; Nakamura, R.; Lucek, E. A.; Takada, T.; Baumjohann, W.; Asano, Y.; Volwerk, M.; Rème, H.; Carr, C.; Frey, H. U.; Runov, A.; Vörös, Z.; Keika, K.
Austria, Japan, Germany, Czech Republic, France, United Kingdom, United States
Abstract
We examined two consecutive plasma sheet oscillation and dipolarization events observed by Cluster in the magnetotail, which are associated with a pseudo-breakup and a small substorm monitored by the IMAGE spacecraft. Energy input from the solar wind and an associated enhancement of the cross-tail current lead to current sheet thinning and plasma sheet oscillations of 3 5 min periods, while the pseudo-breakups occur during the loading phase within a spatially limited area, accompanied by a localized dipolarization observed by DSP TC1 or GOES 12. That is, the so-called “growth phase” is a preferable condition for both pseudo-breakup and plasma sheet oscillations in the near-Earth magnetotail. One of the plasma sheet oscillation events occurs before the pseudo-breakup, whereas the other takes place after pseudo-breakup. Thus there is no causal relationship between the plasma sheet oscillation events and pseudo-breakup. As for the contribution to the subsequent small substorm, the onset of the small substorm took place where the preceding plasma sheet oscillations can reach the region.