Göttingen 2025 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 2: Sun and Heliosphere I

EP 2.4: Vortrag

Montag, 31. März 2025, 17:45–18:00, ZHG101

Global inertial oscillations of the sun — •Laurent Gizon — Max-Planck-Institut für Sonnensystemforchung, 37077 Göttingen — Georg-August-Universität Göttingen, Institut für Astrophysik und Geophysik, 37077 Göttingen

Global oscillations of the Sun consist of two known classes: the well-studied 5-minute acoustic oscillations, which are used in helioseismology, and the recently discovered inertial oscillations with periods on the order of the Sun's rotation period (Gizon et al. 2021). All observed inertial modes propagate more slowly than the equatorial rotation rate and, due to latitudinal differential rotation, these modes have critical latitudes where their phase speeds match the local rotation rate. Linear forward modeling indicates that the mode eigenfrequencies and eigenfunctions are highly sensitive to the Sun's internal differential rotation, as well as to poorly understood properties of solar convection zone, such as the superadiabatic temperature gradient. Additionally, nonlinear simulations (Bekki et al. 2024) suggest that the high-latitude modes with the largest amplitudes are baroclinically unstable and play a significant dynamical role in shaping the Sun's internal rotation profile. In this presentation, we will present a progress report on this highly promising new field of solar physics.

Keywords: solar oscillations; solar rotation; solar convection zone; solar inertial modes