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Observations of Density Cavities and Associated Warm Ion Flux Enhancements in the Inner Magnetosphere
Author(s) -
Ferradas C. P.,
Boardsen S. A.,
Fok M.C.,
Buzulukova N.,
Reeves G. D.,
Larsen B. A.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028326
Subject(s) - magnetosphere , plasmasphere , flux (metallurgy) , ion , physics , van allen probes , atomic physics , van allen radiation belt , plasma , chemistry , nuclear physics , organic chemistry , quantum mechanics
We present a statistical study of density cavities observed in the inner magnetosphere by the Van Allen Probes during four one‐month periods: February 2013, July 2013, January 2014, and June 2014. These periods were chosen to allow the survey of all magnetic local times. We find that density cavities are a recurrent feature of the density profiles of in situ measurements in the inner magnetosphere. We further investigate the correlation between the density cavities and the enhancement of fluxes of warm ions with energies of 10–100 eV. The results show that warm ion flux enhancements associated with the density cavities were observed more frequently for H + , then for He + and the least frequently for O + . The occurrences of the associated flux enhancements were increased when considering only the cavities inside the plasmasphere. Possible mechanisms responsible for the observed warm ion flux enhancements and the role of density cavities on these ion flux enhancements are discussed.