The rise of active region flux tubes in the turbulent solar convective envelope

We use a thin flux tube model in a rotating spherical shell of turbulent convective flows to study how active region scale flux tubes rise buoyantly from the bottom of the convection zone to near the solar surface. We investigate toroidal flux tubes at the base of the convection zone with field strengths ranging from 15kG to 100kG at initial latitudes ranging from 1° to 40° with a total flux of 10²² Mx. We find that the dynamic evolution of the flux tube changes from convection dominated to magnetic buoyancy dominated as the initial field strength increases from 15kG to 100kG. At 100kG, the development of Ω-shaped rising loops is mainly controlled by the growth of the magnetic buoyancy instability. However, at low field strengths of 15kG, the development of rising Ω-shaped loops is largely controlled by convective flows, and properties of the emerging loops are significantly changed compared to previous results in the absence of convection. With convection, rise times are drastically reduced (from years to a few months), loops are able to emerge at low latitudes, and tilt angles of emerging loops are consistent with Joy's law for initial field strengths of ≳40kG. We also examine other asymmetries that develop between the leading and following legs of the emerging loops. Taking all the results together, we find that mid-range field strengths of 40-50kG produce emerging loops that best match the observed properties of solar active regions.