STRUCTURE OF A FLUID DISK AROUND A MAGNETIZED COMPACT OBJECT IN THE PRESENCE OF A SELF-CONSISTENT TOROIDAL MAGNETIC-FIELD

We examine a rotating thick-disk equilibrium in the presence of external gravity and intrinsic dipolar magnetic field due to a nonrotating central object. The solutions we have found show that the pressure and density equilibrium profiles are strongly modified by a self-consistently generated toroidal magnetic field. By drawing an analogy with the Couette flow, a stability criterion for the derived solutions is obtained. It is found that such an equilibrium cannot support a toroidal magnetic field of arbitrary strength. The magnetic field line topology is such that kinks develop in the field line structure. Such kinks will probably give rise to instabilities for a strong toroidal component of the magnetic field.