ABSTRACT:
Wave particle interactions play an important role in radiation belt electron dynamics in the Earth’s inner magnetosphere. In particular, whistler-mode chorus waves, which are generated by energetic electrons injected from the plasmasheet, are known to effectively accelerate low energy seed electron population to relativistic energies, thus playing a key role in creating “killer” electrons with energy up to several MeV in the outer radiation belt. On the other hand, chorus waves also cause electron precipitation into the loss cone and subsequently produce diffuse and pulsating aurora in the upper atmosphere. Using observations from the recently launched twin Van Allen probes, we show the analysis on an interesting event during a double dip geomagnetic storm, in which the first dip of the storm causes major loss of radiation belt electrons, whereas the second dip of the storm leads to very rapid acceleration (< ~12 hours) of electrons up to ~7 MeV. In-situ chorus wave measurements from the EMFISIS instrument on the Van Allen probes together with electron measurements on low-altitude satellites (POES) as a proxy for chorus wave amplitudes provide comprehensive information on chorus wave activity during the evolution of the entire double dip storm. Based on this observed chorus wave information, we simulate radiation belt electron evolution caused by the interaction with chorus waves, and the simulation results show a reasonably good agreement with observation in the heart of the outer radiation belt.