HR: 0800h
AN: SM31A-0394    [Abstracts]
TI: High Energy Electron Precipitation During Expansive Phase Onset
AU: * Spanswick, E
EM: emma@phys.ucalgary.ca
AF: University of Calgary, 2500 University Dr, Calgary, AB T2N1N4 Canada
AU: Donovan, E
EM: eric@phys.ucalgary.ca
AF: University of Calgary, 2500 University Dr, Calgary, AB T2N1N4 Canada
AU: Partamies, N
EM: noora@phys.ucalgary.ca
AF: University of Calgary, 2500 University Dr, Calgary, AB T2N1N4 Canada
AB: Recent work has demonstrated that it is possible to use riometer absorption data to identify dispersionless injections during substorms. The advantage of this technique is that we can map out the spatial extent of the dispersionless injection. For example, we have demonstrated that the dispersionless injection forms initially as an always latitudinally narrow structure and often azimuthally extended structure, consistent with the earlier results of Reeves et al. which were based on in situ high energy electron fluxes [Reeves et al.,Multi-Satellite measurements of the substorm injection region,Geophys. Res. Lett., 17, 2015, 1990]. One disadvantage is that we cannot infer anything about the energy spectrum of the precipitating electrons from the riometer absorption data alone. Another is that our technique can be used to identify an injection based on a specific signature in the time sequence of absorption, but we cannot rule out a dispersionless injection in the absence of that signature. In this presentation, we extend our earlier work by comparing expansive phase riometer data with optical data obtained by the collocated CANOPUS/NORSTAR meridian scanning photometers (MSPs) and All-Sky Imagers (ASIs). More specifically, we compare the 471, 486, 558, and 630 nm auroral emissions with the riometer absorption. Our primary objective is to use the combined optical and riometer data to establish the relationship between discrete (or accelerated) expansion phase aurora and the diffuse precipitation associated with the dispersionless injection. We view this as an essential step towards the use of combined ground-based and in situ observations to constrain substorm models.
DE: 2716 Energetic particles: precipitating
DE: 2730 Magnetosphere: inner
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005