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Particle acceleration during substorm growth and onset
Author(s) -
Williams D. J.,
Mitchell D. G.,
Huang C. Y.,
Frank L. A.,
Russell C. T.
Publication year - 1990
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 - 10.1029/gl017i005p00587
Subject(s) - substorm , physics , particle acceleration , fermi acceleration , acceleration , ion , electron , electric field , current sheet , betatron , atomic physics , magnetic field , plasma , magnetosphere , classical mechanics , nuclear physics , magnetohydrodynamics , quantum mechanics
We present ISEE‐1 observations of ion and electron energization made at ∼11 R E during a substorm event occurring on 2 April 1978. An analysis of the dominant cross‐tail current systems in this event (Mitchell et al., 1990) has allowed us to uniquely associate particle energization processes with the development and/or disruption of the cross‐tail currents. We find that significant ion acceleration occurs as the ions participate in serpentine cross‐tail motion (Speiser, 1965), establishing the dominant plasma sheet current system just prior to onset. As this current disrupts, the magnetic field configuration dipolarizes and further ion energization and the bulk of the electron energization occurs. During dipolarization energization is due primarily to the inductive electric field, including betatron and Fermi acceleration processes.