Rotation of the solar interior:: New results by helioseismic data inversions

We determine the variation of the Sun's angular velocity with latitude and radius by means of a helioseismic inversion of more than 30,000 of p-mode splitting coefficients. These data were obtained from the first set of uninterrupted Doppler images from SOI-MDI ton board the SOHO satellite) in 1996 (Schou et al. 1994), which yield splittings of great accuracy, never obtained in previous sets of data. This allow us to probe rotation in the convection zone and the outer part of the radiative core, and obtain more reliable results closer to the poles (Schou et al. 1998). We are also able to study rotational details in the shear layer (tachocline) located near the base of the convection zone and determine the behaviour of the angular velocity in the solar core, Unfortunately, the data uncertainties for low l degrees result of weak significance in a rotational profile in the deepest layers. In order to infer the rotation of the deep interior accurately, we also invert some sets of data with more accurate splittings of the lowest degree modes (l similar to 1 - 4). Currently, the best data sets for this purpose still come from groundbased networks such as, BISON, IRIS and GONG (Chaplin et al. 1996; Lazreck ct al. 1996, Gavryuseva & Gavryusev 1998). Finally, since these inversions, based on different low-l data still give conflicting solutions in the core, we discuss also the results obtained by inverting the latest accurate low-l data of the GOLF instrument on SOHO.