The effect of an inclined magnetic field on solar oscillation frequencies

The radiative interior of the sun could be hiding a large-scale magnetic field, which might not be axisymmetric about the observed rotation axis. Using helioseismic data, we estimate that the strength of any such relic field must be less than about 30 MG, if the field is axisymmetric about the rotation axis. The shape oblateness caused by a field at this limiting strength is about 5-10 x 10 exp -6. Stronger fields can be accommodated by the helioseismic data if they are inclined to the rotation axis. We further conclude that the convention zone and at least the outer part of the radiative interior rotate on the same axis.