The Magnetic Mechanism for Hotspot Reversals in Hot Jupiter Atmospheres

Abstract Magnetically driven hotspot variations (which are tied to atmospheric wind variations) in hot Jupiters studied using nonlinear numerical simulations of a shallow-water magnetohydrodynamic (SWMHD) system and linear analysis equatorial SWMHD waves. In hydrodynamic models, mid-to-high-latitude geostrophic circulations known cause net west-to-east thermal energy transfer, which drives offsets eastward. We find that strong toroidal magnetic field can obstruct these transporting circulations. This results winds aligning with the generates westward Lorentz force accelerations regions, ultimately causing offsets. subsequent we this reversal mechanism has an wave analogy terms planetary-scale magneto-Rossby compare our findings three-dimensional MHD simulations, both quantitatively qualitatively, identifying link between mechanics magnetically reversals. use developed theory identify physically motivated criteria, be used place constraints on fields ultra-hot observed hotspots.