Connection Between Chorus Wave Amplitude and Background Magnetic Field Inhomogeneity: A Parametric Study

Abstract

Abstract Whistler mode chorus waves frequently appear as discrete, repetitive, and quasi‐monochromatic emissions with frequency chirping. With different wave amplitude and frequency chirping rate, chorus waves have been observed not only in the magnetosphere of the Earth but also in the magnetospheres of other planets, such as Saturn and Jupiter. Motivated by understanding different properties of chorus waves at these planets using the recently proposed “Trap‐Release‐Amplify” (TaRA) model, we perform a parametric study using Particle‐In‐Cell simulations by varying background magnetic field inhomogeneity and the corresponding threshold hot electron number density. We show the consistency between simulation results and theoretical predictions for threshold hot electron number density, chorus chirping rate, and wave amplitude. Our results suggest the significant role of the background magnetic field inhomogeneity in affecting chorus wave properties, including its amplitude at different planets as predicted by the TaRA model.

Keywords

• whistler mode chorus wave
• background magnetic field inhomogeneity
• PIC simulation
• TaRA model