- University of Southampton, Astronomy, Physics and Astronomy, Southampton, United Kingdom of Great Britain – England, Scotland, Wales (c.soriano-guerrero@soton.ac.uk)
Hot Jupiters are extreme planetary environments where strong stellar irradiation drives fast atmospheric winds in partially ionised gas. Under these
conditions, magnetic fields can interact with atmospheric dynamics, potentially modifying circulation patterns and contributing to atmospheric heating through Ohmic dissipation. Despite its importance, the role of magnetohydrodynamic (MHD) processes in hot Jupiter atmospheres remains less explored than purely hydrodynamic models.
In this work we investigate magnetic induction and field amplification in the atmospheres of hot Jupiters using a hierarchy of local MHD models with
increasing physical complexity. We begin with three dimensional ideal MHD simulations of a narrow atmospheric column representative of the dayside
radiative layers of ultra-hot Jupiters. These simulations show that strong zonal winds efficiently wind the background magnetic field, generating intense
toroidal components concentrated in shear layers near pressures of order ~1 bar. The resulting fields can reach kilogauss strengths, locally, and are
sustained by meridional currents without requiring an internal dynamo.
We then incorporate non-ideal MHD effects, including Ohmic diffusion, Hall drift, and ambipolar diffusion, using thermodynamic and wind profiles derived from global circulation models of several hot Jupiters, including WASP-76b, WASP18b, WASP-121b and HD 209458b. While magnetic winding remains the
dominant mechanism, Hall and ambipolar terms modify the structure and orientation of the magnetic field in low-pressure regions.
Finally, we explore fully three-dimensional non-ideal MHD configurations including small-scale perturbations. These perturbations trigger the formation of
coherent magnetic structures superimposed on the dominant toroidal field and lead to additional meridional components.
Overall, our results show that magnetic effects in hot Jupiter atmospheres are highly nonlinear and spatially structured, and may play an important role in
atmospheric energy dissipation. This highlights the need to incorporate MHD processes more consistently in future global circulation and evolutionary models.
How to cite: Soriano Guerrero, C.: MHD atmospheric simulations of Hot Jupiters to study non-ideal effects and turbulence, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-136, https://doi.org/10.5194/epsc2026-136, 2026.
