Energetic Particle Dynamics and Magnetospheric Plasma Waves: Observations and Future Missions

Natural emissions in the form of plasma waves occur in the terrestrial magnetosphere and include both broad band emissions (e.g., plasmaspheric hiss) and discrete emissions (e.g., Electromagnetic Ion Cyclotron- EMICwaves, whistler mode chorus). These plasma waves not only energize but also precipitate charged particles present in the terrestrial radiation belts (for reviews see Kanekal and Miyoshi 2021; Millan and Thorne, 2007; Thorne 2010). It is well known that large solar wind structures such as coronal mass ejections and corotating interaction regions lead to enhanced wave activity and lead to enhanced relativistic electron populations as well as their precipitation into the atmosphere. Less known are the radiation belt electron interaction with mesoscale transient solar wind structures such as periodic density structures (PDS). Here we report upon a recent event study of relativistic electron response to PDS in the heart of the radiation belts. We provide an overview of energetic electron dynamics ranging from rapid energization resulting from interplanetary shocks (IP) to mesoscales PDSs. We show pitch angle distribution response of highly relativistic electrons to plasma waves as well as loss due to electron microburst precipitation. Electron precipitation is known to influnce atmospheric chemistry and therby global climate change. We also describe a mission concept to quanitfy systematically electron microburst loss into the atmosphere.