Bonn 2020 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 5: Sun and Heliosphere III

EP 5.1: Invited Talk

Wednesday, April 1, 2020, 14:00–14:30, H-HS VIII

New Opportunities with the Regularized κ−Distribution — •Edin Husidic — Institut für Theoretische Physik, Lehrstuhl IV: Plasma-Astroteilchenphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany

The solar wind is a rich field for various plasma waves and instabilites, which can be studied by solving the kinetic dispersion relation. By assuming small perturbations, a linear dispersion analysis is often sufficient, and except some special cases, the general solutions of the dispersion relation are usually obtained using numerical solvers. Among the standard solvers dedicated to a certain family of model distribution functions, e.g., Maxwellian or Kappa power-laws, those that allow for arbitraty distributions are more practical, as the measured particle distributions do not follow idealized distributions. In the solar wind the observed distributions deviate from a Maxwellian, showing enhanced suprathermal tails, which can be well fitted by the so-called standard κ−distribution (SKD). Due to a series of unphysical limitations and characteristics of the SKD, such as diverging velocity moments, a non-extensive entropy and a non-desirable contribution to macroscopic quantities from unphysical superluminal particles, the regularized κ-distribution (RKD) has been introduced. The RKD can reproduce as limit cases both the Maxwellian and the SKD with the benefit of overcoming the limitations of an SKD. The dispersion curves as well as growth and damping rates of different plasma instabilities based on the (anisotropic) RKD are computed and discussed.