Timing and location of phenomena during auroral breakup: A case study Original Research Article

We performed a multi-instrument ground-based and satellite study of substorm-related phenomena during auroral breakup. Our study is limited to the short (a few minutes) time interval around the breakup onset. A mapping made on the basis of event-oriented mangnetospheric model places the pre-breakup arc into the near-Earth region (r ≈ 10 RE) where thin and intense current sheet develops. Disruption of the current sheet was observed in the same region. The plasmoid was observed in the mid-tail. Backtracing the plasmoid onset time and location confirmed that reconnection related to the substorm onset could operate in the near-Earth thin current sheet. These observations are in agreement with the idea that the reconnection and current disruption signatures, as well as auroral breakup are different manifestations of the one process.