Electromagnetic ion cyclotron wave modeling during the geospace environment modeling challenge event

We investigate the temporal evolution and the spatial distribution of electromagnetic ion cyclotron (EMIC) waves during the 8–11 June 2001 geomagnetic storm, one of the storms selected for study by the Geospace Environment Modeling program. Generations of EMIC waves in the H+, He+, and O+ bands are simulated using the kinetic ring current-atmosphere interactions model with a self-consistent magnetic field and a ray tracing code. Simulations show that strong wave gain occurs in the afternoon sector at L > 5 and overlaps with a high-density plasmaspheric drainage plume. EMIC wave gain maximizes during the main phase and decreases in the recovery phase. We find that EMIC wave gain is stronger in the He+ band than in the other two bands in the inner magnetosphere, except the region of low L (< 3) where the H+ band is dominant due to an enhancement in the ring current anisotropy. Little wave gain is obtained for the O+ band. Comparison with in situ EMIC events and EMIC event proxies at five geosynchronous satellites shows consistence in the temporal and local time evolution of the wave distribution. Our simulations of the EMIC wave distribution also agree with proton aurora at subauroral latitudes observed from the Imager for Magnetopause-to-Aurora Global Exploration satellite.

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