Magnetic flux and particle transport in the plasma sheet

摘要

Sets of 12 long-term averaged three-dimensional (3-D) data-based models were created to show how the structure of the plasma sheet depends upon particle transport rates and upon magnetic flux transport rates. The volume V and content N of unit flux tubes and the entropy parameters PV 5/3 and TV 2/3 were evaluated for each model. It was found that V and PV 5/3 depend only weakly on the transport rates. In contrast, N was much smaller and TV 2/3 was much larger when the transport rates were large. Most parameters depended strongly upon x. The long-term averaged x dependence of PV 5/3 was closely associated with the x dependence of N. Earthward and tailward transport nearly cancelled during periods of slow and moderate flow. The transport and spatial dependence of the measured variables therefore were attributed primarily to the confined, intermittent, high-temperature, low-density, fast or bursty bulk flows. Several mechanisms were described that can contribute to the observed earthward decreases of N and of PV 5/3 or to the pressure balance inconsistency. A sequence of events involving reconnection was shown to be one mechanism that is capable of producing the observed spatial variations.