Paper#: 138
Poster #:
Session Name: Workshop 6A: Ionospheric Process
Room: 200ABC
Day: Thursday
Time: 3:00-3:25 p.m.
Abstract Title: Energy Deposition and Ion Outflow Near the Nightside Polar Boundary during Substorms: A FAST Perspective
PresentSurname: Carlson, C.W.
All Authors: C.W. Carlson, J.P. McFadden
Abstract : The FAST satellite traverses the low altitude auroral zones in a few minutes, providing a limited but nearly instantaneous signature of the magnetospheric regions mapping to the aurora. During substorms, the most intense precipitating electron energy fluxes and intense ion outflows are found in the polar cap boundary regions, which lie just inside the open magnetic field boundary identified by polar rain electrons and VDIS ion bursts. Auroral images identify this region with the substorm bulge. Here bursty, magnetic field-aligned electron fluxes are associated with intense Alfven waves rather than the quasi-DC potential structures characteristic of inverted-V auroral arcs. Conjugate Auroral images observed by the UVI instrument on POLAR show corresponding turbulent spatial structure. These signatures suggest that this region maps to bursty flows and magnetic merging regions in the magnetotail. Low frequency waves generated by these precipitated electron bursts produce intense ion heating and outflows that are comparable to cusp outflow fluxes. Successive substorms associated with magnetic storms produce even larger ion outflows and enhanced oxygen composition. Since these ions are injected onto newly closed magnetic field lines, they will become adiabatically heated as they convect into the inner magnetosphere, where they will contribute to the ring current.