Multipoint Measurements to Determine EMIC Wave Structure and its Relation to Solar Wind and Magnetospheric Drivers

Abstract:

Wave-particle interactions provide a primary source of scattering and energization of energetic electrons in the Earth’s radiation belts. Electromagnetic ion cyclotron (EMIC) waves are one intense wave mode observed in the inner magnetosphere that have been shown to contribute to scattering and loss of both energetic electrons and ions. Using multi-point measurements from the Heliospheric Systems Observatory, including NASA’s Van Allen Probes, we examine the properties and source regions of EMIC waves in the inner magnetosphere. In particular, we explore the formation and evolution of plasma structures as they relate to observed wave growth, as well as the effects of these waves on Earth's radiation belts. Two case studies are presented in detail, one driven by weak convection producing waves spanning the nightside inner magnetosphere, and the other driven by narrow solar wind structures resulting in discrete bursts of wave activity on the dayside. These events highlight the critical role solar wind and magnetospheric drivers play in dictating the evolution and extent of magnetospheric plasma and wave processes.