Simultaneous Observations and Combined Effects of Electromagnetic Ion Cyclotron Waves and Magnetosonic Waves

Magnetosonic (MS) waves and Electromagnetic ion cyclotron (EMIC) waves are important plasma waves in the magnetosphere. Using the Van Allen Probes observations from 2012 to 2017, we constructed the global distribution of simultaneous occurrence of MS and EMIC waves. We found a total of 214 events and the waves distribute from the noon sector to the duskside. Furthermore, we quantitatively analyze the combined effects of both waves on protons and electrons by calculating the particle diffusion coefficients and 2-D Fokker-Planck diffusion simulations. The simulation results show the combined effects of MS and EMIC waves. High-frequency EMIC waves and intense MS waves at low proton harmonics are essential for the enhanced proton acceleration at several hundred eV and enhanced electron loss at several MeV. Our results provide new sights into understanding the distribution of MS and EMIC waves and evaluating their combined effects on the evolution of energetic particles.

Automated summary

By analyzing data from the Van Allen Probes, researchers have determined the global distribution of simultaneous occurrence of Magnetosonic (MS) and Electromagnetic ion cyclotron (EMIC) waves in the magnetosphere. Their study also quantitatively analyzes the combined effects of these waves on protons and electrons, showing the importance of high-frequency EMIC waves and intense MS waves for proton acceleration and electron loss. This research provides new insights into understanding the distribution of MS and EMIC waves and evaluating their combined effects on energetic particles.