Open AccessEvidence for chorus‐driven electron acceleration to relativistic energies from a survey of geomagnetically disturbed periods
Author(s) -
Meredith Nigel P.,
Cain Michelle,
Horne Richard B.,
Thorne Richard M.,
Summers Danny,
Anderson Roger R.
Publication year - 2003
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 - 10.1029/2002ja009764
Subject(s) - substorm , physics , electron , van allen radiation belt , magnetosphere , chorus , plasmasphere , van allen probes , flux (metallurgy) , geophysics , local time , population , computational physics , atmospheric sciences , plasma , nuclear physics , art , statistics , literature , materials science , mathematics , demography , sociology , metallurgy
We perform a survey of the plasma wave and particle data from the CRRES satellite during 26 geomagnetically disturbed periods to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by Doppler‐shifted cyclotron resonant interactions with whistler mode chorus. Relativistic electron flux enhancements associated with moderate or strong storms may be seen over the whole outer zone (3 < L < 7), typically peaking in the range 4 < L < 5, whereas those associated with weak storms and intervals of prolonged substorm activity lacking a magnetic storm signature (PSALMSS) are typically observed further out in the regions 4 < L < 7 and 4.5 < L < 7, respectively. The most significant relativistic electron flux enhancements are seen outside of the plasmapause and are associated with periods of prolonged substorm activity with AE greater than 100 nT for a total integrated time greater than 2 days or greater than 300 nT for a total integrated time greater than 0.7 days. These events are also associated with enhanced fluxes of seed electrons and enhanced lower‐band chorus wave power with integrated lower‐band chorus wave intensities of greater than 500 pT 2 day. No significant flux enhancements are seen unless the level of substorm activity is sufficiently high. These results are consistent with a local, stochastic, chorus‐driven electron acceleration mechanism involving the energization of a seed population of electrons with energies of a few hundred keV to relativistic energies operating on a timescale of the order of days.