Mapping of the Precipitation Regions to the Plasma Sheet

The progress in the mapping of the auroral regions in the Earth's polar ionosphere to outer magnetosphere reflects our growing understanding of the gross magnetospheric structure. Several “natural tracers” were identified and used by us for the mapping scheme advocated for more than a decade. A “natural tracer” is a plasma boundary identifiable at different altitudes which, from physical reasons, is aligned along the magnetic flux tube (accounting for cross-field convection). The boundaries' locations describe the current state of the magnetosphere. The following tracers to the tail were used in our studies: the low-latitude Soft Electron precipitation Boundary; the large-scale Convection Boundary, or an Alfven Layer; the Plasmapause; the Stable Trapping Boundary for high energy electrons; the precipitating hot ion Isotropy Boundary; the two types of Velocity-Dispersed Ion Structures: VDIS-1 (adjacent to an electron inverted-V structure within the oval), and VDIS-2 (just poleward from the oval). A new “Wall Region” concept related to non-adiabatic (non-MHD) ion dynamics allows to add its effects in the list of “natural tracers”. Another newly discovered structure in the tail is the Low Energy Layer of counter-streaming low-energy (