Dipolarizing flux bundles in the cis-geosynchronous magnetosphere: relationship between electric fields and energetic particle injections

TitleDipolarizing flux bundles in the cis-geosynchronous magnetosphere: relationship between electric fields and energetic particle injections
Publication TypeJournal Article
Year of Publication2016
AuthorsLiu, J, Angelopoulos, V, Zhang, X-J, Turner, DL, Gabrielse, C, Runov, A, Li, J, Funsten, HO, Spence, HE
JournalJournal of Geophysical Research: Space Physics
Date Published01/2016
Keywordsdipolarization front; dipolarizing flux bundle; energetic particle injection; geosynchronous orbit; magnetic storm; Particle acceleration
AbstractDipolarizing flux bundles (DFBs) are small flux tubes (typically < 3 RE in XGSM and YGSM) in the nightside magnetosphere that have magnetic field more dipolar than the background. Although DFBs are known to accelerate particles, creating energetic particle injections outside geosynchronous orbit (trans-GEO), the nature of the acceleration mechanism and the importance of DFBs in generating injections inside geosynchronous orbit (cis-GEO) are unclear. Our statistical study of cis-GEO DFBs using data from the Van Allen Probes reveals that just like trans-GEO DFBs, cis-GEO DFBs occur most often in the pre-midnight sector, but their occurrence rate is ~1/3 that of trans-GEO DFBs. Half the cis-GEO DFBs are accompanied by an energetic particle injection and have an electric field three times stronger than that of the injectionless half. All DFB injections are dispersionless within the temporal resolution considered (11 seconds). Our findings suggest that these injections are ushered or produced locally by the DFB, and the DFB's strong electric field is an important aspect of the injection generation mechanism.
URLhttp://doi.wiley.com/10.1002/2015JA021691
DOI10.1002/2015JA021691
Short TitleJ. Geophys. Res. Space Physics


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