Göttingen 2025 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 2: Sun and Heliosphere I

EP 2.5: Talk

Monday, March 31, 2025, 18:00–18:15, ZHG101

Nonlinear saturation mechanism of solar high-latitude inertial modes — •Muneeb Mushtaq, Damien Fournier, and Laurent Gizon — Max-Planck Institute for Solar System Research, Goettingen, Germany

At high latitudes the solar rotation rate drops fast with increasing latitude and is linearly unstable. In this presentation we discuss the nonlinear saturation mechanism, which controls the amplitude of the high-latitude solar inertial modes. Using nonlinear numerical simulations of purely toroidal modes on the sphere, we show that the bifurcation is supercritical.This justifies the use of the weakly nonlinear theory to model the development of the disturbance amplitude and to determine to what value it saturates. We find a simple relationship between the mode amplitude and the linear growth rate of the mode.

Keywords: Inertial modes; Navier-Stokes equation; Weakly nonlinear