Erlangen 2026 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 9: Sun and Heliosphere III
EP 9.1: Talk
Thursday, March 19, 2026, 13:45–14:00, KH 01.019
Langmuir waves in astrophysical Druyvesteyn plasmas — Simon Tischmann1, Rudi Gaelzer2, Dustin Lee Schroeoder1, Marian Lazar3, and •Horst Fichtner1 — 1Theoretische Physik IV, Ruhr-Universit\"at Bochum, Germany — 2Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Brazil — 3Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Belgium
We present a new model for linear dispersion studies in astrophysical plasmas, by introducing astrophysical Druyvesteyn plasmas. This model can reproduce not only high-energy tails, as observed in situ in the solar wind, but also low-energy flat-tops of the velocity distributions, like those of electrons in interplanetary shocks. The dispersion relation of longitudinal waves is derived in terms of the newly introduced Druyvesteyn dispersion function. The dispersion curves as well as damping rates of high-frequency Langmuir waves are numerically computed for the isotropic case using the ALPS code, and their analytical approximations are provided in the limit of weak damping. This way we offer a new tool for modeling longitudinal waves, and in particular Langmuir waves, that may be useful for other astrophysical systems which are in non-equilibrium states as evidenced by direct in-situ measurements, like the solar corona and planetary environments, as well as by indirect observations of nonthermal sources of waves and emissions.
Keywords: non-equlilibrium plasma; linear dispersion theory; Langmuir waves; Druyvesteyn plasma