The Dynamics of the Solar Radiative Zone

Abstract

The dynamics of the solar radiative interior are still poorly constrained by comparison to the convective zone. This disparity is even more marked when we attempt to derive meaningful temporal variations. Many data sets contain a small number of modes that are sensitive to the inner layers of the Sun, but we found that the estimates of their uncertainties are often inaccurate. As a result, these data sets allow us to obtain, at best, a low resolution estimate of the solar core rotation rate down to approximately 0.2R. We present inferences based on mode determination resulting from an alternate peak-fitting methodology aimed at increasing the amount of observed modes that are sensitive to the radiative zone, while special care was taken in the determination of their uncertainties. This methodology has been applied to MDI and GONG data, for the whole Solar Cycle 23, and to the newly available HMI data. The numerical inversions of all these data sets result in the best inferences to date of the rotation in the radiative region. These results and the method used to obtain them are discussed. The resulting profiles are shown and analyzed, and the significance of the detected changes discussed.