Correlated observations of substorm effects in the near‐Earth region and the deep magnetotail

We present simultaneous observations of energetic particle measurements from the geosynchronous satellite 1982–019 and magnetic field, electron plasma, and energetic proton and electron measurements obtained with ISEE 3 in the deep tail. The data are supplemented by ground magnetograms. A substorm occurred on March 22, 1983, close to 0300 UT as identified in the ground magnetograms and by a particle injection at geosynchronous orbit. About 10 min later, ISEE 3 observed (at a distance of ∼130 RE in the deep tail) magnetic field, plasma, and energetic particle signatures consistent with the passage of a plasmoid. After the passage of the plasmoid the satellite enters shortly into a lobelike environment, in which an energetic proton beam is observed. High‐resolution magnetic field data are indicative of small‐scale structures in the postplasmoid plasma sheet. From the plasma sheet flow speed during the plasmoid's passage it is concluded that the 0300 UT substorm is responsible for its origin. This allows an approximate timing of the plasmoid release at a near‐earth neutral line and of the plasma sheet recovery after substorm onset, and it indicates a close relationship between processes in the near‐earth plasma sheet and the deep tail during substorms.