EMIC Waves Observed Throughout the Inner Magnetosphere Driven by Abrupt Enhancement of the Solar Wind Pressure
Zuxiang Xue, Zhigang Yuan, Xiongdong Yu, Dan Deng, Zheng Huang, Tero Raita
Abstract
Abstract Electromagnetic ion cyclotron (EMIC) waves were simultaneously observed in the day‐ and night‐side region driven by a sudden enhancement of the solar wind pressure on 12 July 2013, which was registered by both ground stations and space satellites. The amplitude enhancements of EMIC waves are well correlated to the intensification of the ambient magnetic field caused by the enhanced solar wind pressure pulse. Due to the northward interplanetary magnetic field, the magnetic field intensification is found to appear globally in the inner magnetosphere, which is predicted by field model outputs and evidenced by satellite observations. As a result, the observed nightside protons become more anisotropic, which further promotes proton instabilities and amplifies pre‐existing EMIC waves. Our findings provide direct observational evidence that enhanced solar wind pressure pulse can directly drive the ring current ion dynamics and EMIC wave evolutions throughout the inner magnetosphere.