ICS-13 Abstract View

 

The Role of Auroral Streamers, Pseudo-Breakups, and Substorms in Particle Energization
Henderson, M.G., mghenderson@lanl.gov (1)
Morley, S.K., smorley@lanl.gov (1)
Woodroffe, J.R., jwoodroffe@lanl.gov (1)
Jordanova, V.K., vania@lanl.gov (1)
Dispersionless and dispersed particle injections associated with substorms have been studied for many years based on observations acquired primarily at geosynchronous orbit. A general picture that has emerged is that particles are energized and rapidly transported/organized behind an "injection boundary" that penetrates closer to Earth in some magnetic local time sector (e.g. the so-called double-spiral injection boundary model). Although this seems to provide a very good description of injections at geosynchronous orbit, recent observational and modeling studies have shown that the picture is often more complex farther downtail. It is currently thought that particle injections result when electrons and ions become energized as they interact with the more localized strong dynamic electric and magnetic fields associated with Earthward-directed flow bursts produced at reconnection sites. The details of how this mechanism leads to the formation of a more coherent, broad "injection boundary" structure in the inner magnetosphere is not currently understood.

We examine this problem using multi-point observations of energetic particle injections together with global auroral imagery. Since auroral streamers and torches are produced by flow bursts (and their near-Earth braking) in the tail, they can be used to understand how observed particle injections relate (spatially and temporally) to the flow bursts. During disturbed intervals, we find that strong injections at geosynchronous orbit are typically associated with new pseudo-breakups and substorm onsets rather than with large-scale streamers and torch structures (although there are in fact cases where the later can lead to strong injection activity.) Simulated injections using the SHIELDS Particle Tracing Model (PTM) are presented as an organizing framework.
(1) Space Science and Applications, Los Alamos National Laboratory, Los Alamos NM, USA