Interaction of field-aligned cold plasma flows with an equatorially-trapped hot plasma: Electrostatic shock formation

The author addresses a problem in the study of plasmaspheric refilling. Most studies look at the flow of cold ionospheric plasma, and its trapping in flux tubes. These calculations do not address the observational fact that there are highly anisotropic, hot ion populations in these flux tubes, and possible interactions of these plasmas. The author sets up a simple calculation to see how a cold plasma will interact with such a trapped anisotropic hot ion plasma. The model shows that this interaction facilitates the formation of electrostatic shocks, since the ions form a potential barrier to the inflowing cold plasma. The conclusion is that this interaction can drastically affect the cold plasma flow, and can result in eventual mixing which can lead to instability in the velocity distribution for the ions