München 2019 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 4: Sun and Heliosphere II
EP 4.4: Vortrag
Mittwoch, 20. März 2019, 12:15–12:30, HS 19
On the entropy of plasmas described with regularized κ-distributions — •Horst Fichtner1, Klaus Scherer1, Marian Lazar1,2, Hans Fahr3, and Zoltan Vörös4 — 1Institut für Theoretische Physik IV, Ruhr-Universität Bochum, Germany — 2Centre for Mathematical Plasma Astrophysics, Katholieke Universiteit Leuven, Belgium — 3Argelander Institut für Astronomie, Universität Bonn, Germany — 4Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Recently, the debate about the physics foundations of so-called (standard) κ-distributions (SKDs), which describe plasma constituents with power-law velocity distributions, has intensified. Amongst other critical features, the extensitivity of entropy has been questioned in the context of a theoretical foundation for the SKDs. In classical thermodynamics the entropy is an extensive quantity, i.e. the sum of the entropies of two subsystems in equilibrium with each other is equal to the entropy of the full system consisting of the two subsystems. We demonstrate here, by employing the recently introduced regularized κ-distributions (RKDs) that entropy can be defined as an extensive quantity even for such power-law-like distributions that truncate exponentially.