A METHOD FOR INCORPORATING THE EFFECTS OF LARGE-SCALE MAGNETIC-FIELDSIN THE STUDY OF STELLAR STRUCTURE AND VARIABILITY

This paper presents a means of modifying the equations of stellar stru cture and evolution (including mixing-length theory) for the effects o f a large-scale magnetic field confined within a star. The derivations are carried out to a consistent degree of approximation. The resultin g equations are incorporated within a standard stellar evolution code which has been modified for the study of structural changes occurring over time steps as short as 1 year. The code is tested by constructing a solar model containing a ''magnetic perturbation'' which is presume d to mimic the fields associated with the solar dynamo. Examples of th e detailed consequences of such a perturbation on the structure of a s olar model are described for two different field intensities and distr ibutions.