Quasilinear Approach of the Whistler Heat-Flux Instability in the Solar Wind

Abstract

The hot beaming (or strahl) electrons responsible for the main electron heat-flux in the solar wind are believed to be self-regulated by the electromagnetic beaming instabilities, also known as the heat-flux instabilities. Here we report the first quasi-linear theoretical approach of the whistler unstable branch able to characterize the long-term saturation of the instability as well as the relaxation of the electron velocity distributions. The instability saturation is not solely determined by the drift velocities, which undergo only a minor relaxation, but mainly from a concurrent interaction of electrons with whistlers that induces (opposite) temperature anisotropies of the core and beam populations and reduces the effective anisotropy. These results might be able to (i) explain the low intensity of the whistler heat-flux fluctuations in the solar wind (although other explanations remain possible and need further investigation), and (ii) confirm a reduced effectiveness of these fluctuations in the relaxation and isotropization of the electron strahl and in the regulation of the electron heat-flux.

accepted for publication MNRAS

References in corpus (4)

• Whistler mode waves and the electron heat flux in the solar wind: Cluster observations
• Experimental determination of whistler wave dispersion relation in the solar wind
• Whistler wave generation by halo electrons in the solar wind
• The Interplay of the Solar Wind Core and Suprathermal Electrons: A Quasilinear Approach for Firehose Instability

Cited by in corpus (8)

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• On quasi-parallel whistler waves in the solar wind
• Quasilinear approach of the cumulative whistler instability in fast solar winds: Constraints of electron temperature anisotropy
• Electromagnetic Ion-Ion Instabilities in Space Plasmas: Effects of Suprathermal Populations
• Whistler instabilities from the interplay of electron anisotropies in space plasmas: A quasilinear approach
• On the interplay of solar wind proton and electron instabilities: Linear and quasi-linear approaches
• Quantifying the diffusion of suprathermal electrons by whistler waves between 0.2 and 1 AU with Solar Orbiter and Parker Solar Probe