POLOIDAL FIELD OF A SLOWLY ROTATING AXISYMMETRICAL ROTATOR

The cold plasma ejection problem from the magnetosphere of a slow axisymmetric rotator is solved in the MHD approximation. Rotation is assumed to cause a small magnetospheric perturbation. We take the unperturbed (OMEGA=0) solution to be a spherically symmetric solution with radially divergent lines of force. From the regularity condition on the poloidal magnetic field at the Alfven surface, a correct expression is obtained for the toroidal magnetic field generated by the rotation. Analytic expressions proportional to OMEGA2, are obtained for the first corrections to the poloidal field. The solution shows that the toroidal field has the effect of drawing the poloidal field toward the axis of rotation.