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EP: Fachverband Extraterrestrische Physik
EP 11: Sun and Heliosphere IV
EP 11.8: Talk
Thursday, April 3, 2025, 15:30–15:45, ZHG101
Temperature anisotropy instabilities of solar wind electrons with regularized Kappa-halos resolved with ALPS — •Dustin Schröder1, Horst Fichtner1, Marian Lazar1,2, Daniel Verscharen3, and Kris Klein4 — 1Ruhr-Universität Bochum — 2Katholieke Universiteit Leuven — 3University College London — 4University of Arizona
Space plasmas in various astrophysical setups are often hot & diluted, making them highly susceptible to waves/fluctuations, which are generally self-generated & maintained by kinetic instabilities. In this sense, we have in-situ observational evidence from the solar wind & planetary environments, which reveal not only wave fluctuations at kinetic scales of electrons & protons, but also non-equilibrium distributions of particle velocities. We report on the progress made in achieving a consistent modeling of the instabilities generated by temperature anisotropy, taking example of those induced by anisotropic electrons: whistler & firehose instabilities. The effects of the main electron populations, the quasi-thermal core & the suprathermal halo indicated by the observations, are captured. The low-energy core is bi-Maxwellian, & the halo is described for the first time by a regularized bi-κ-distribution (RKD), which was recently introduced to fix the inconsistencies of standard κ-distributions. In the absence of an analytical RKD dispersion kinetic formalism, the dispersion relation & (in)stability properties are directly solved numerically using the Aribitrary Linear Plasma Solver (ALPS). The results have an increased degree of confidence, considering the successful testing of ALPS on previous results.
Keywords: regularized Kappa distribution (RKD); Solar wind electrons; Temperature anisotropy instabilities; ALPS; Core-Halo distributions