Whistler instability stimulated by the suprathermal electrons present in space plasmas

Abstract

In the absence of efficient collisions, deviations from thermal equilibrium of plasma particle distributions are controlled by the self-generated instabilities. The whistler instability is a notorious example, usually responsible for the regulation of electron temperature anisotropy $A=T_{\perp }/T_{\parallel }>$ (with $\perp ,\parallel$ respective to the magnetic field direction) observed in space plasmas, e.g., solar wind and planetary magnetospheres. Suprathermal electrons present in these environments change the plasma dispersion and stability properties, with expected consequences on the kinetic instabilities and the resulting fluctuations, which, in turn, scatter the electrons and reduce their anisotropy. In order to capture these mutual effects we use a quasilinear kinetic approach and PIC simulations, which provide a comprehensive characterization of the whistler instability under the influence of suprathermal electrons. Analysis is performed for a large variety of plasma conditions, ranging from low-beta plasmas encountered in outer corona or planetary magnetospheres to a high-beta solar wind characteristic to large heliospheric distances. Enhanced by the suprathermal electrons, whistler fluctuations stimulate the relaxation of temperature anisotropy, and this influence of suprathermals increases with plasma beta parameter.

accepted for publications at Astrophysics and Space Science

References in corpus (5)

• Electron energy partition across interplanetary shocks: I. Methodology and Data Product
• Cumulative effect of Weibel-type instabilities in counterstreaming plasmas with non-Maxwellian anisotropies
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• The Interplay of the Solar Wind Core and Suprathermal Electrons: A Quasilinear Approach for Firehose Instability
• Quasilinear approach of the cumulative whistler instability in fast solar winds: Constraints of electron temperature anisotropy

Cited by in corpus (8)

• Alternative high plasma beta regimes of electron heat-flux instabilities in the solar wind
• On quasi-parallel whistler waves in the solar wind
• Linear Dispersion Theory of Parallel Electromagnetic Modes for Regularized Kappa-Distributions
• Towards a general quasi-linear approach for the instabilities of bi-Kappa plasmas. Whistler instability
• Whistler instabilities from the interplay of electron anisotropies in space plasmas: A quasilinear approach
• Electromagnetic ion cyclotron instability stimulated by the suprathermal ions in space plasmas: A quasi-linear approach
• A new low-beta regime for unstable proton firehose modes in bi-Kappa distributed plasmas
• On the interplay of solar wind proton and electron instabilities: Linear and quasi-linear approaches