Observations of tail dynamics using ground and space based instruments during a period of multiple substorm events

Abstract

We present initial observations from an ongoing investigation into the dynamics of the magnetotail during a period of multiple substorms. The investigation coordinates data from ground and space-based instruments including the Cluster and IMAGE spacecraft, SuperDARN and ground magnetometers during the period 00:00UT to 05:00UT on 25th August, 2003. The first substorm expansion phase, which is preceded by two pseudo-breakups at 00:38UT and 00:57UT, takes place between 01:11UT and 01:50UT during which time IMAGE WIC(FUV) data for the Southern auroral oval shows enhanced auroral activity almost solely in the post-midnight sector and the occurrence of auroral streamers within the auroral bulge. SuperDARN map potential analysis shows a flow diversion with a northern hemisphere footprint that is conjugate to a southern hemisphere auroral streamer. During this time, Cluster CIS and FGM instruments detect the passage of under-populated flux tubes, or plasma bubbles, and a field rotation event, discussed as a flux rope. These observations agree with current predictions on the relationship between streamers and under-populated flux tubes in the tail from the Chen and Wolf model.