Premium
Excitation of Storm Time Pc5 ULF Waves by Ring Current Ions Based on the Drift‐Kinetic Simulation
Author(s) -
Yamakawa T.,
Seki K.,
Amano T.,
Takahashi N.,
Miyoshi Y.
Publication year - 2019
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 - 10.1029/2018gl081573
Subject(s) - ring current , physics , magnetosphere , excitation , atomic physics , resonance (particle physics) , ion , excited state , kinetic energy , computational physics , van allen probes , toroid , geophysics , magnetic field , plasma , van allen radiation belt , classical mechanics , quantum mechanics
Abstract Storm time Pc5 waves are considered to be excited through the drift‐bounce resonance by ring current ions associated with the injection from the magnetotail. Using the Geospace Environment Modeling System for Integrated Studies–Ring Current simulation, a drift‐kinetic and self‐consistent model for ring current particles, we investigate the excitation mechanism of these waves in the inner magnetosphere. The power spectra of electromagnetic field fluctuations show the excitation of both poloidal and toroidal mode waves in Pc5 frequency range. It is found that these waves are fundamental mode waves with the azimuthal wave number m ~ − 20 and excited through the drift resonance with the drifting ions with energies of 80–120 keV. The simulation indicates that global distribution of wave power coincides with the positive local growth rate mainly contributed by the positive phase space density gradient in energy.