Simulation of Chorus Wave Excitation in the Compressed/Stretched Dipole Magnetic Field

Abstract

Whistler mode chorus waves are strong electromagnetic emissions frequently observed in the Earth's magnetosphere. They can appear as rising tones, falling tones, and hiss-like emissions in dynamic spectra (Gao et al., 2014;Li et al., 2012). In general, the chorus waves with distinct elements are repetitive Lu et al., 2021;Shue et al., 2015). There is usually a power gap around 0.5 𝐴𝐴 𝐴𝐴𝑐𝑐𝑐𝑐 (where 𝐴𝐴 𝐴𝐴𝑐𝑐𝑐𝑐 is the electron gyrofrequency at the equator), naturally forming lower (0.1-0.5 𝐴𝐴 𝐴𝐴𝑐𝑐𝑐𝑐 ) and upper (0.5-0.8 𝐴𝐴 𝐴𝐴𝑐𝑐𝑐𝑐 ) band chorus (Burtis &

Direct Observation of Rising‐Tone Chorus Triggered by Enhanced Solar Wind Pressure

“…In addition, the compressional ULF waves can also modulate chorus waves by changing magnetic field gradient (Li et al., 2022). Simulation results have clearly shown that the change of the inhomogeneity or curvature of background magnetic field can affect the fine structure of chorus waves (Katoh & Omura, 2013; Kong et al., 2023). Although several studies have reported the appearance and quench of chorus waves caused by the solar wind dynamic pressure (Fu et al., 2012; Liu et al., 2017; Yue et al., 2017; Zhou et al., 2015), there is still no direct observation on the modulation of fine structures of chorus waves by solar wind dynamic pressure.…”