We present the first three-dimensional circulation models for extrasolar gas giant atmospheres with geometrically and energetically consistent treatments of magnetic drag and ohmic dissipation .
Atmospheric resistivities are continuously updated and calculated directly from the flow structure , strongly coupling the magnetic effects with the circulation pattern .
We model the hot Jupiters HD 189733b ( T _ { \mathrm { eq } } \approx 1200 K ) and HD 209458b ( T _ { \mathrm { eq } } \approx 1500 K ) and test planetary magnetic field strengths from 0 to 30 G. We find that even at B = 3 G the atmospheric structure and circulation of HD 209458b are strongly influenced by magnetic effects , while the cooler HD 189733b remains largely unaffected , even in the case of B = 30 G and super-solar metallicities .
Our models of HD 209458b indicate that magnetic effects can substantially slow down atmospheric winds , change circulation and temperature patterns , and alter observable properties .
These models establish that longitudinal and latitudinal hot spot offsets , day-night flux contrasts , and planetary radius inflation are interrelated diagnostics of the magnetic induction process occurring in the atmospheres of hot Jupiters and other similarly forced exoplanets .
Most of the ohmic heating occurs high in the atmosphere and on the day side of the planet , while the heating at depth is strongly dependent on the internal heat flux assumed for the planet , with more heating when the deep atmosphere is hot .
We compare the ohmic power at depth in our models , and estimates of the ohmic dissipation in the bulk interior ( from general scaling laws ) , to evolutionary models that constrain the amount of heating necessary to explain the inflated radius of HD 209458b .
Our results suggest that deep ohmic heating can successfully inflate the radius of HD 209458b for planetary magnetic field strengths of B \geq 3 - 10 G .