HELIOSEISMOLOGY DATA AND THE SOLAR DYNAMO

Some of the difficulties raised by recent helioseismology data for dynamo wave models of the solar cycle are addressed. These data have been interpreted as indicating that the latitudinal variations of angular velocity across the convection zone are approximately independent of depth. Theoretical frequency splittings are calculated for several types of model of the Sun's internal rotation profile, and it is confirmed that models in which the rotation rate is constant on concentric cylinders are incompatible with the observed frequency-splitting data. It is also shown that the radial surface models may be compatible with these data, but only if parameters for the surface rotation rate are permitted to depart from those derived from surface spectroscopic data. Another class of model, in which the rotation rate profiles are not independent of depth, is investigated, and these models are shown to accommodate the helioseismology data at least as well as the radial surfaces model. The implications for dynamo models and for the dynamics of the convection zone are con