On the magnetic field required for driving the observed angular-velocity   variations in the solar convection zone
  A putative temporally varying circulation-free magnetic-field configuration is inferred in an equatorial segment of the solar convection zone from the helioseismologically inferred angular-velocity variation, assuming that the predominant dynamics is angular acceleration produced by the azimuthal Maxwell stress exerted by a field whose surface values are consistent with photospheric line-of-sight measurements. 
H. M. Antia, S. M. Chitre, D. O. Gough
astro-ph.SR