2024/11/25 by Aurélie Astoul, Astoul, Aurélie, Adrian J. Barker +1
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Solar and Space Plasma Dynamics #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2411.16534
openalex publication_date 2024/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Stars and gaseous planets are magnetised objects but the influence of magnetic fields on their tidal responses and dissipation rates has not been well explored. We present the first exploratory nonlinear magnetohydrodynamic (MHD) simulations of tidally-excited waves in incompressible convective envelopes harbouring an initial dipolar magnetic field. Simulations with weak magnetic fields exhibit tidally-generated differential rotation in the form of zonal flows (like in the purely hydrodynamic case) that can modify tidal dissipation rates from prior linear predictions. Moreover, tidal waves and zonal flows affect the amplitude and structure of the magnetic field, notably through creation of toroidal fields via the Ω-effect. In contrast, simulations with strong magnetic fields feature severely inhibited zonal flows, due to large-scale magnetic stresses, excitation of torsional waves, or magnetic instabilities. We predict that the different regimes observed for weak and strong magnetic fields may be both relevant for low-mass stars when using turbulent values of the magnetic Prandtl number.