title: Acceleration and loss of relativistic electrons during small geomagnetic storms.
abstract: Past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms (Dst> -50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result in flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.
authors.affiliation: Department of Physics and Astronomy Dartmouth College Hanover New Hampshire USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Anderson
authors.affiliation: Department of Physics and Astronomy Dartmouth College Hanover New Hampshire USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Millan
authors.affiliation: Space Science and Applications Los Alamos National Laboratory Los Alamos New Mexico USA; New Mexico Consortium Los Alamos New Mexico USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Reeves
authors.affiliation: Space Science and Applications Los Alamos National Laboratory Los Alamos New Mexico USA; New Mexico Consortium Los Alamos New Mexico USA.
authors.forename: R H W
authors.initials: RH
authors.lastname: Friedel
keywords: geomagnetic storms; geosynchronous relativistic electron flux; radiation belt dynamics; solar wind