Characteristics of Ion Flow in the Quiet State of the Inner Plasma Sheet
AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
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We use AMPTEIRM and ISEE 2 data to study the properties of the high beta Beta sub iota 0.5 plasma sheet, the inner plasma sheet IPS. Bursty bulk flows BBFs are excised from the two databases, and the average flow pattern in the non-BBF quiet IPS is constructed. At local midnight this ensemble-average flow is predominantly duskward closer to the flanks it is mostly earthward. The flow pattern agrees qualitatively with calculations based on the Tsyganenko 1987 model T87, where the earthward flow is due to the ensemble-average cross tail electric field and the duskward flow is the diamagnetic drift due to an inward pressure gradient. The IPS is on the average in pressure equilibrium with the lobes. Because of its large variance the average flow does not represent the instantaneous flow field. Case studies also show that the non-BBF flow is highly irregular and inherently unsteady, a reason why earthward convection can avoid a pressure balance inconsistency with the lobes. The ensemble distribution of velocities is a fundamental observable of the quiet plasma sheet flow field. Convection, Magnetosphere, Plasma Sheet.
- Atmospheric Physics
- Guided Missiles
- Fluid Mechanics
- Plasma Physics and Magnetohydrodynamics