Interaction of EMIC waves with thermal plasma and radiation belt particles

Electromagnetic ion cyclotron waves are excited during the enhanced convective injection of plasmasheet ions into the inner magnetosphere. Waves grow rapidly near the magnetic equatorial plane reaching amplitudes up to 10 nT. Such intense waves induce scattering of cyclotron resonant ions at a rate comparable to the strong diffusion limit, causing rapid ion precipitation into the atmosphere in localized regions where the waves are present. The waves also resonate with relativistic electrons at energies typically above 0.5 MeV. Such scattering, which could provide a major loss process for relativistic outer zone electrons during the main phase of a magnetic storm, is confined to high-density regions just inside the plasmapause or within dayside drainage plumes. As EMIC waves propagate to higher latitude, their wave normal angle becomes highly oblique. This allows Landau resonant interaction with thermal electrons, which can heat the electron population in the outer plasmasphere to several eV, contributing to the heat flux that drives Stable Auroral Red (SAR) arcs. During the propagation to higher latitude, EMIC waves can also experience cyclotron resonant damping by heavy thermal ions, leading to ion conic distributions, which are observed near the equator