Evolution of flows and fields from the reconnection region to the inner edge of the plasma sheet
Abstract
Recent results from THEMIS's first tail season have revealed the location of substorm onset in the tail and the critical role of magnetic reconnection in disrupting the cross-tail currrent. The second THEMIS tail season enables more frequent captures of the pre-onset tail neutral sheet simultaneously at multiple downtail distances. Using one event, where all satellites were well positioned near the tail current sheet, we find that while closed plasma sheet field line reconnection preconditions the inner magnetosphere and the ionosphere, the most dynamic energy release takes place in association with significant flux transport further down the tail, likely associated with lobe reconnection. Tracing the energy flow from the reconnection site to the inner edge of the plasma sheet, we study the evolution of the magnetic field dipolarization and waves. Wave activity is confined at or behind a sharp dipolarization front, well within the recently reconnected flux. Wave characteristics are self-similar from 20Re to 10Re, exhibiting electrostatic shocks and non-linear whistlers. Electron acceleration or scattering by these waves may result in auroral signatures previously reported during such tail structures. However, Alfven waves related to current closure of the approaching dipolarization front may also be responsible for aspects of the inferred auroral precipitation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMSM13B1603A
- Keywords:
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- 2744 MAGNETOSPHERIC PHYSICS / Magnetotail;
- 7829 SPACE PLASMA PHYSICS / Kinetic waves and instabilities;
- 7835 SPACE PLASMA PHYSICS / Magnetic reconnection