ICS-13 Abstract View

 

Do substorms play a role in energizing the inner magnetosphere?
Gabrielse, C., cgabrielse@ucla.edu (1)
Gkioulidou, M., Malamati.Gkioulidou@jhuapl.edu (2)
Historically, the term substorm was coined by Professor S. Chapman in the 1960's to refer to the notion that they are smaller-scale events that build up a geomagnetic storm, and hence the ring current. Many observations and simulations have shown that injections play a significant role in cumulatively feeding the ring current [e.g. Akasofu et al., 1974; Gkioulidou et al., 2014; Yang et al., 2015]. However, several observations demonstrate a disconnect in our understanding of the relationship of smaller-scale magnetospheric injections that deliver energy to the ring current and the definition of the auroral substorm [Ohtani et al., 2006; Dubyagin et al., 2011; Sergeev et al., 2012]. Intriguing observations of similar types of injections have also been made in other planetary magnetospheres such as those of Jupiter and Saturn [Kasahara et al., 2010; Jackman et al., 2013] that may illuminate the general nature of this problem.

Substorm particle injections are also known to provide a seed population to the radiation belts that can be further energized via wave-particle interactions and transport. Because the injected populations are anisotropic, they can generate the whistler-mode chorus waves capable of both accelerating them to MeV energies as well as scattering them into the loss cone. The balance of sources and losses in the radiation belts is a complex problem, such that the radiation belts respond differently to similar storms [Reeves et al., 2003]. This is further illustrated by recent statistics [Forsyth et al., 2016] showing that only 50% of substorms result in enhanced total radiation belt electron content. What role substorms play in energizing the inner magnetosphere is an open question, one which we intend to discuss with the community in this Socratic Dialogue.
(1) University of California, Los Angeles, CA 90025
(2) John Hopkins University Applied Physics Lab, Laurel, MD 20723