Velocity-space Signatures of Resonant Energy Transfer between Whistler Waves and Electrons in the Earth’s Magnetosheath

Abstract

Wave–particle interactions play a crucial role in transferring energy between electromagnetic fields and charged particles in space and astrophysical plasmas. Despite the prevalence of different electromagnetic waves in space, there is still a lack of understanding of fundamental aspects of wave–particle interactions, particularly in terms of energy flow and velocity-space characteristics. In this study, we combine a novel quasilinear model with observations from the Magnetospheric Multiscale mission to reveal the signatures of resonant interactions between electrons and whistler waves in magnetic holes, which are coherent structures often found in the Earth’s magnetosheath. We investigate the energy transfer rates and velocity-space characteristics associated with Landau and cyclotron resonances between electrons and slightly oblique propagating whistler waves. In the case of our observed magnetic hole, the loss of electron kinetic energy primarily contributes to the growth of whistler waves through the n = −1 cyclotron resonance, where n is the order of the resonance expansion in linear Vlasov–Maxwell theory. The excitation of whistler waves leads to a reduction of the temperature anisotropy and parallel heating of the electrons. Our study offers a new and self-consistent understanding of resonant energy transfer in turbulent plasmas.

Pickup Ion Modulation on Plateau-like Turbulence in the Martian Magnetosheath

“…However, direct evidence is needed to support the contribution of PUIs to the formation of plateau-like spectra. Numerous studies suggest that the magnetic field spectrum comprises diverse wave modes and structures, including Alfvén waves, fast-mode/slow-mode magnetosonic waves, and coherent structures such as filamentary Alfvén vortices, current sheets, and magnetic holes (Sahraoui et al 2006;Alexandrova 2008;Vörös et al 2008;Lion et al 2016;Jiang et al 2022Jiang et al , 2024. The spectral shape and location of the break point suggest the presence of narrowband waves, incoherent and unpolarized fluctuations, and coherent structures with significant amplitudes (Lion et al 2016).…”

Whistler Waves in the Quasi‐Parallel and Quasi‐Perpendicular Magnetosheath

“…Shi et al (2020) showed that whistlers at the bow shock effectively scatter electrons and modify the electron distribution. In a recent numerical study, Jiang et al (2023) modeled a MSH electron distribution during the excitation of whistler waves. They observed that energy transfer mainly occurred through the first-order cyclotron resonance and that the interaction caused a reduction of the electron temperature anisotropy.…”