Effects of Magnetic Dips on the Propagation of Electromagnetic Ion Cyclotron Waves

Abstract

AbstractRecent studies have found that magnetic dips resulting from the diamagnetic motion of injected plasmas can provide a favorable environment for electromagnetic ion cyclotron (EMIC) wave excitation. However, another critical question how magnetic dips affect the propagation of EMIC waves remains uncovered. In this paper, with plasma environment as well as wave properties observed in a typical event, theoretical analysis about this topic has been provided. Our results show that in this event both H+ band and He+ band EMIC waves can be constrained in the magnetic dip, which is consistent with the wave emissions observed inside the magnetic dip. The energetic protons have also been found to fall around the saturated states, suggesting a stable balance built among EMIC waves, energetic protons, and magnetic structures. Our results provide one new insight into the EMIC wave propagation inside a magnetic dip and their important roles in the dynamics of magnetic dips.