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The Global Statistical Response of the Outer Radiation Belt During Geomagnetic Storms
Author(s) -
Murphy K. R.,
Watt C. E. J.,
Mann I. R.,
Jonathan Rae I.,
Sibeck D. G.,
Boyd A. J.,
Forsyth C. F.,
Turner D. L.,
Claudepierre S. G.,
Baker D. N.,
Spence H. E.,
Reeves G. D.,
Blake J. B.,
Fennell J.
Publication year - 2018
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 - 10.1002/2017gl076674
Subject(s) - van allen radiation belt , adiabatic process , geomagnetic storm , physics , storm , adiabatic invariant , van allen probes , radiation , population , earth's magnetic field , atmospheric sciences , phase space , electron , acceleration , computational physics , meteorology , magnetosphere , nuclear physics , magnetic field , classical mechanics , quantum mechanics , demography , sociology
Using the total radiation belt electron content calculated from Van Allen Probe phase space density, the time‐dependent and global response of the outer radiation belt during storms is statistically studied. Using phase space density reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and nonadiabatic effects and revealing a clear modality and repeatable sequence of events in storm time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant ( μ )‐dependent behavior in the seed (150 MeV/G), relativistic (1,000 MeV/G), and ultrarelativistic (4,000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, while the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ dependent and occurs at low μ first, appearing to be repeatable from storm to storm.