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Predicting electromagnetic ion cyclotron wave amplitude from unstable ring current plasma conditions
Author(s) -
Fu Xiangrong,
Cowee Misa M.,
Jordanova Vania K.,
Gary S. Peter,
Reeves Geoffrey D.,
Winske Dan
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023303
Subject(s) - physics , magnetosphere , ring current , instability , van allen radiation belt , cyclotron , computational physics , electron , van allen probes , amplitude , atomic physics , plasma , mechanics , nuclear physics , optics
Electromagnetic ion cyclotron (EMIC) waves in the Earth's inner magnetosphere are enhanced fluctuations driven unstable by ring current ion temperature anisotropy. EMIC waves can resonate with relativistic electrons and play an important role in precipitation of MeV radiation belt electrons. In this paper, we investigate the excitation and saturation of EMIC instability in a homogeneous plasma using both linear theory and nonlinear hybrid simulations. We have explored a four‐dimensional parameter space, carried out a large number of simulations, and derived a scaling formula that relates the saturation EMIC wave amplitude to initial plasma conditions. Such scaling can be used in conjunction with ring current models like ring current‐atmosphere interactions model with self‐consistent magnetic field to provide global dynamic EMIC wave maps that will be more accurate inputs for radiation belt modeling than statistical models.