plasmapause.

The occurrence of large-scale plasma convection within the Earth’s magnetosphere, driven by the external flow of the solar wind, has long been recognised as being of fundamental significance in determining the properties, structure and dynamics of magnetospheric plasma populations. There continues to be controversy over the kind of physical processes which couple the magnetosphere to the external shocked solar wind (magnetosheath) and which initiate the convection cycle by transporting plasma and magnetic flux from the dayside boundary into the geomagnetic tail. The two main possibilities have been a viscous-like interaction associated with wave-particles interactions and plasma diffusion, and magnetic reconnection between the wind and the flux. The two processes may coexist.

Jones’ Antarctic Survey remote-sensed the plasmapause in 1981. It provides a source of natural radio emission. Radio noise is observed by spacecraft in the plasmatrough (the cavity of low-density plasma between the Earth’s plasmasphere and its magnetosheath. Escaping non-thermal radio continuum (overlapping so that it appears continuous) can be thought of as distinct beams of radiation, with different frequencies from different regions of the plasmapause, and not continuum at all. After multiple reflections the beams from numerous sources are scattered and merge to produce the radio continuum.