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Nonstorm loss of relativistic electrons in the outer radiation belt
Author(s) -
Katsavrias Ch.,
Daglis I. A.,
Turner D. L.,
Sandberg I.,
Papadimitriou C.,
Georgiou M.,
Balasis G.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl066773
Subject(s) - magnetopause , physics , magnetosheath , van allen radiation belt , magnetosphere , substorm , van allen probes , geophysics , electron , solar wind , magnetic reconnection , astrophysics , geomagnetic storm , computational physics , plasma , quantum mechanics
We report observations of electron Phase Space Density (PSD) dropout and evidence that supports the loss mechanism of magnetopause shadowing and outward radial diffusion during a nonstorm period characterized by persistently positive values of the SYM ‐ H index. On 14 April 2013 an electron PSD dropout of 2 orders of magnitude was observed at the nightside magnetosphere by the Van Allen Probes. The magnetopause shadowing was associated with a strong pulse attributed to the arrival of an interplanetary coronal mass ejection. It is shown, for the first time in detail, that significant losses to the magnetosheath may occur even in the absence of significant reconnection and magnetic storm activity. Signatures of substorm injections that penetrate the outer belt and enhance the low‐energy electrons were also observed right after the interplanetary pressure pulse. Moreover, particle measurements from THEMIS constellation also show a PSD depletion in the dayside magnetosphere.