An Analytic Study of the Perpendicularly Propagating Electromagnetic Drift Instabilities in the Magnetic Reconnection Experiment

[摘要] A local linear theory is proposed for a perpendicularly propagating drift instability driven by relative drifts between electrons and ions. The theory takes into account local cross-field current, pressure gradients and modest collisions as in the Magnetic Reconnection Experiment (MRX) [10]. The unstable waves have very small group velocities in the direction of the pressure gradient, but have a large phase velocity near the relative drift velocity between electrons and ions in the direction of cross-field current. By taking into account the electron-ion collisions and applying the theory in the Harris sheet, we establish that this instability could be excited near the center of the Harris sheet and have enough efoldings to grow to large amplitude before it propagates out of the unstable region. Comparing with the other magnetic reconnection related instabilities (LHDI, MTSI et.) studied previously, we believe the instability we find is a favorable candidate to produce anomalous resistivity because of its unique wave characteristics, such as electromagnetic component, large phase velocity, and small group velocity in the cross current layer direction.

[发布日期] 2008-12-03

[学科分类] 原子、分子光学和等离子物理

[关键词] AMPLITUDES;DRIFT INSTABILITY;ELECTRON-ION COLLISIONS;ELECTRONS;INSTABILITY;MAGNETIC RECONNECTION;PHASE VELOCITY;PRESSURE GRADIENTS;VELOCITY Drift Instability;MHD Instabilities