Modes of convection in the magnetotail

The flow of plasma in the Earth's magnetotail cannot reach a steady state, since steady adiabatic convection would lead to too high pressure of the associated magnetic flux tubes closer to the Earth, the so-called pressure catastrophy. The natural way to avoid the pressure catastrophy is to significantly reduce the flux tube volume by reconnection, and observations show a near-Earth reconnection line typically around 20-25 Re downtail. Earthward flows from this reconnection line are rather bursty and typically seen outside of 10 Re. At this point they are strongly braked by the here dominant dipolar magnetic field. The pressure gradients piled up by the flow lead to the substorm current wedge, and possibly other substorm phenonema observed in the Earth's ionosphere. When more and more flux tubes are piled up, the dipolarization front moves tailward and finally shuts off near-Earth reconnection.