SIMULATING THE KINEMATIC DYNAMO FORCED BY HETEROCLINIC CONVECTIVE VELOCITY-FIELDS

We report on the integration of the kinematic dynamo problem in a sphe rical domain forced by velocity fields that are convective fluid flows resulting from a bifurcation analysis of the spherical Benard problem . We derive a code based on generalized spherical harmonics that ensur es a divergence-free magnetic field. We determine the growth or decay of a magnetic field in the kinematic dynamo equation for various physi cally relevant velocity fields which are stationary as well as time-pe riodic and chaotic. Velocity signals that are produced by heteroclinic cycles are used as an input to an energy-saturated kinematic dynamo e quation that limits the growth of the linearly unstable modes. Prelimi nary calculations indicate the possibility of reversals of the magneti c field for this case of forcing.