Kinetic properties of the electron current sheet and its neighbor magnetic islands
Abstract
Kinetic physics of magnetic reconnection is key to the impulsive energy release of a current sheet in collisionless plasmas. We have developed a methodology combining multi-spacecraft data and PIC simulations to delineate inflow and exhaust regions within the reconnection layer, and reconstruct the time history and topology of reconnection. The methodology has been applied to a few magnetotail reconnection events, and enabled the following discoveries. One, bursts of energetic electrons are found in the interior of magnetic islands [Chen et al., Nature Physics, 4, 19-23, 2008]. Two, two reconnection layers, including a spatially extended electron current sheet (ecs), are separated by a non-stationary magnetic island with dimensions of a few ion inertial lengths (di). Three, the electron density decreases toward the ecs by a factor of 3-4 within one di, peaks at the ecs center, and increases by about an order of magnitude from the ecs toward the center of the neighbor magnetic island. Four, whistler waves and flat-topped electron distributions are observed simultaneously with energetic electrons at density compression sites within the di-scale island between two reconnection layers. Five, across the ecs, nonlinear Langmuir waves are abundant, but no electrostatic solitary waves are observed. Six, oxygen ions exhibit single beams in the inflow region, counter-streaming beams at the island boundary near the ecs, and triple beams in island interior near the ecs. In this paper, we present our methodology and new findings, and discuss the impact of these findings on our understanding of collisionless magnetic reconnection.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMSM31B1733C
- Keywords:
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- 2700 MAGNETOSPHERIC PHYSICS (6939);
- 2723 Magnetic reconnection (7526;
- 7835);
- 2740 Magnetospheric configuration and dynamics;
- 2744 Magnetotail;
- 2788 Magnetic storms and substorms (7954)