Temporal and Spatial Structure of Substorm Associated High Energy Particle Precipitation
Abstract
The evolution of the high-energy electron population through the substorm cycle has been studied directly with in situ observations such as those provided by the LANL-SOPA instruments, and indirectly through precipitation seen via riometers, X-ray imagers, and other instruments. Ground-based and other remote sensing techniques provide the advantage of being able to track such disturbances in both space and time, with caveats including the fact that information about the energy of the precipitating particles is limited. Using data from the 13 instrument NORSTAR (formerly CANOPUS) riometer array in north-central Canada, we are examining a large number of substorm events. We are focussing on a transient ``spike'' of significant absorption that occurs during most substorm expansive phases. Seen from any one station, the spike lasts several minutes. More globally, it typically takes tens of minutes to propagate across the NORSTAR array. The propagation is in general a combination of azimuthal (ie., East or West) and poleward. In this paper, we present a statistical comparision between the propagation characteristics of the spike and other substorm features such as dipolarization, auroral bulge, Pi2s, and injections. As well, we present a detailed analysis of several events. Our objective is to determine the magnetospheric source of this transient high energy precipitation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFMSM51B0528S
- Keywords:
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- 2451 Particle acceleration;
- 2716 Energetic particles;
- precipitating;
- 2736 Magnetosphere/ionosphere interactions;
- 2768 Plasmasphere;
- 2788 Storms and substorms