Nonlinear Evolution of the Whistler Heat Flux Instability

Abstract

We use the one-dimensional TRISTAN-MP particle-in-cell code to model the nonlinear evolution of the whistler heat flux instability that was proposed by Gary et al. (1999) and Gary & Li (2000) to regulate the electron heat flux in the solar wind and astrophysical plasmas. The simulations are initialized with electron velocity distribution functions typical for the solar wind. We perform a set of simulations at various initial values of the electron heat flux and β e . The simulations show that parallel whistler waves produced by the whistler heat flux instability saturate at amplitudes consistent with the spacecraft measurements. The simulations also reproduce the correlations of the saturated whistler wave amplitude with the electron heat flux and β e revealed in the spacecraft measurements. The major result is that parallel whistler waves produced by the whistler heat flux instability do not significantly suppress the electron heat flux. The presented simulations indicate that coherent parallel whistler waves observed in the solar wind are unlikely to regulate the heat flux of solar wind electrons.

Exploring the Properties of the Electron Strahl at 1 AU as an Indicator of the Quality of the Magnetic Connection Between the Earth and the Sun

“…5) Another possible reason why a strahl may not be detected at 1 AU is because of plasma-wave instabilities that may have disrupted the strahl, (e.g. Gary and Saito, 2007;Kuzichev et al, 2019;Lopez et al, 2019;Vasko et al, 2019;Versharen et al, 2019;Jeong et al, 2020;Micera et al, 2020). Parameterization of instability thresholds is needed and then a matching of strahlchange locations with plasma-parameter changes is needed to test the instability possibility.…”

Electron Diffusion and Advection During Nonlinear Interactions With Whistler‐Mode Waves

“…[2017, 2018], and Kuzichev et al. [2019]). This narrowing occurs as the instability saturates and the anisotropy decreases, reducing the maximum frequency with positive growth rate (i.e., the condition on marginal instability is satisfied in a smaller ranger of frequencies) (Kennel & Petschek, 1966; Ossakow et al., 1972; Tao et al., 2017).…”

Mapping for nonlinear electron interaction with whistler-mode waves

“…Whistler waves are electromagnetic emissions within the frequency range from the lower-hybrid up to electron cyclotron frequency widely observed in space 1,46,80,94,96 and laboratory 69,83 plasmas. These waves are generated by various types of electron distributions with thermal anisotropy 38,87 , beam distributions 8,42,91,92 , or both 9,48,51 , and they play an important role in the isotropisation of originally unstable electron distributions 29,44,74 . A classical theory of whistler wave resonant interaction with electrons is the quasi-linear theory 37,45,88 that assumes a broad spectrum of low amplitude waves.…”