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EMIC wave scale size in the inner magnetosphere: Observations from the dual Van Allen Probes
Author(s) -
Blum L. W.,
Bonnell J. W.,
Agapitov O.,
Paulson K.,
Kletzing C.
Publication year - 2017
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 - 10.1002/2016gl072316
Subject(s) - magnetosphere , physics , ring current , van allen probes , van allen radiation belt , computational physics , spacecraft , geophysics , emic and etic , electromagnetic spectrum , astrophysics , astronomy , plasma , optics , nuclear physics , sociology , anthropology
Estimating the spatial scales of electromagnetic ion cyclotron (EMIC) waves is critical for quantifying their overall scattering efficiency and effects on thermal plasma, ring current, and radiation belt particles. Using measurements from the dual Van Allen Probes in 2013–2014, we characterize the spatial and temporal extents of regions of EMIC wave activity and how these depend on local time and radial distance within the inner magnetosphere. Observations are categorized into three types—waves observed by only one spacecraft, waves measured by both spacecraft simultaneously, and waves observed by both spacecraft with some time lag. Analysis reveals that dayside (and H+ band) EMIC waves more frequently span larger spatial areas, while nightside (and He+ band) waves are more often localized but can persist many hours. These investigations give insight into the nature of EMIC wave generation and support more accurate quantification of their effects on the ring current and outer radiation belt.