Open AccessStatistical analysis of phase space density buildups and dropouts
Author(s) -
Shprits Yuri,
Daae Marianne,
Ni Binbin
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja016939
Subject(s) - plasmasphere , solar wind , dynamic pressure , earth's magnetic field , physics , local time , space weather , van allen probes , electron density , geophysics , geodesy , geology , van allen radiation belt , computational physics , magnetosphere , magnetic field , mechanics , plasma , statistics , mathematics , quantum mechanics
The dynamics of the radiation belt Phase Space Density (PSD) is analyzed using measurements from four spacecraft taken during two hundred days in 1990 and 1991. In situ measurements from CRRES, Akebono, GPS, and GEO and a realistic model of the magnetic field are used to infer values of PSD. The inferred values of PSD are assimilated into a radial diffusion model by means of Kalman filtering to produce a reanalysis of the relativistic electron PSD during this time interval. The statistical analysis shows that the plasmapause location is well correlated with the location of the peak of PSD. Positive innovation outside of the plasmasphere shows that local acceleration is present in the trough region. The peak of PSD and the local source, as inferred from the innovation, are displaced inward during times of increased geomagnetic activity. Analysis of non‐adiabatic dropouts in PSD shows that the dropouts often coincide with sudden increases in the solar wind dynamic pressure. Approximately 73% of the dropouts can be associated with the simultaneous sudden jumps (>7 nPa over several hours) in the solar wind dynamic pressure, approximately 15% could be associated with small jumps or gradual increases in solar wind dynamic pressure, and the remaining 12%, which consists of only 3 events, occurred during relatively steady solar wind dynamic pressure.