Mixing motions in the Sun and solar-type stars

Abstract

We consider here some of the consequences of adiabatic dynamically driven motions within the radiative inner region of the Sun and solar-type stars for which it is assumed that an oblique magnetic field is trapped below the convection zone. The internal motions are due to both centrifugal and magnetic forces and we discuss their behaviour over the lifetime of a solar-type star. We assume, following Mestel¹, that stars of mass ∼1 M⊙ have a magnetic field which is contained by the outer convection zones of solar-type stars. We propose that if such a field exists in the interior of the Sun and other solar-type stars then coupled with the possibility of a rapidly rotating core as suggested by Claverie et al.², we have a possible mechanism for diffusive-type motions which could influence solar models³. Furthermore, we show that if the nutation frequency of an oblique magnetic rotator corresponds to the solar cycle then the magnetic field will need to be of the order of 10⁷ G. All of the relevant theory and equations may be found in refs 4 and 5 and here we merely outline some of the pertinent assumptions and results contained therein.