Erlangen 2026 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 6: Sun and Heliosphere I
EP 6.4: Talk
Wednesday, March 18, 2026, 15:00–15:15, KH 01.019
Strongly localized heating in polytropic expanding stellar wind models — •Lukas Westrich1,2, Bidzina Shergelashvili1,2,3,4, and Horst Fichtner1 — 1Theoretical Physics IV, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany — 2Centre for Computational Helio Studies, Faculty of Natural Sciences and Medicine, Ilia State University, Cholokashvili Ave. 3/5, 0162 Tbilisi, Georgia — 3Evgeni Kharadze Georgian National Astrophysical Observatory, M. Kostava street 47/57, 0179 Tbilisi, Georgia — 4Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften, Schmiedlstrasse 6, 8042 Graz, Austria
In this talk, we present novel polytropic, expanding solar wind models that include a strongly localized heating source. After introducing the (quasi-)discontinuous solar wind models, we discuss the polytropic index and its use as a simplified description of the energy balance in the expanding plasma. In addition to the *background* energy-balance process captured by the polytropic index and for a few solutions a Hollweg type like heat conduction, we introduce a strongly localized heating mechanism - possibly due to acoustic waves - and construct new polytropic stellar wind models, both analytical and numerical. These new stellar wind models may be of particular interest in light of recent Parker Solar Probe observations, which reveal strongly varying wind streams and the presence of acoustic waves close to the Sun.
Keywords: solar wind; stars:winds; hydrodynamics; methods: analytical; methods: numerical