Global and local disturbances in the magnetotail during reconnection

oleh: T. V. Laitinen, R. Nakamura, A. Runov, H. Rème, E. A. Lucek

Format: Article
Diterbitkan: Copernicus Publications 2007-05-01

Deskripsi

We examine Cluster observations of a reconnection event at <I>x</I><sub>GSM</sub>=&minus;15.7 <I>R<sub>E</sub></I> in the magnetotail on 11 October 2001, when Cluster recorded the current sheet for an extended period including the entire duration of the reconnection event. The onset of reconnection is associated with a sudden orientation change of the ambient magnetic field, which is also observed simultaneously by Goes-8 at geostationary orbit. Current sheet oscillations are observed both before reconnection and during it. The speed of the flapping motions is found to increase when the current sheet undergoes the transition from quiet to active state, as suggested by an earlier statistical result and now confirmed within one single event. Within the diffusion region both the tailward and earthward parts of the quadrupolar magnetic Hall structure are recorded as an x-line passes Cluster. We report the first observations of the Hall structure conforming to the kinks in the current sheet. This results in relatively strong fluctuations in <I>B<sub>z</sub></I>, which are shown to be the Hall signature tilted in the <I>yz</I> plane with the current sheet.