Electron vorticity observed during fundamental physical processes in near-Earth space
Abstract
While vorticity, defined as the curl of the velocity, has been broadly used in fluid and plasma physics, the lack of multipoint measurements with spacecraft separations on small scales (e.g., less than tens electron inertial lengths) and the usual relatively low time resolution of particle data have hindered addressing electron vorticity in near-Earth space before the launch of the MMS spacecraft. We present MMS observations of electron vorticity observed 1) around reconnecting current sheets, 2) within a flux rope, and 3) in the magnetosheath. Using these events, we show 1) how enhancements of the electron vorticity (greater than the electron gyrofrequency) in the vicinity of the electron diffusion region (EDR) delineate the multi-scale reconnection boundaries , 2) how the electron vortex is associated with intense electric fields (hundreds mV/m) inside the flux rope, and 3) how the electron-only vortices form in the turbulent magnetosheath. We discuss the origins of enhanced electron vorticity in these events to distinguish generation mechanisms either invoking the electron Kelvin-Helmholtz instability or wave activity in the lower-hybrid band. Effects of the enhanced electron vorticity on the modification of magnetic field topology and evolution of related physical processes follow. Our study sheds new light on electron vorticity, a physical quantity that has been underutilized in space physics, its ubiquity and roles and effects on the diverse fundamental physical processes occurring in near-Earth space.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM21C3185H
- Keywords:
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- 7835 Magnetic reconnection;
- SPACE PLASMA PHYSICS;
- 7845 Particle acceleration;
- SPACE PLASMA PHYSICS;
- 7863 Turbulence;
- SPACE PLASMA PHYSICS;
- 7867 Wave/particle interactions;
- SPACE PLASMA PHYSICS