Magnetic buoyancy in the Sun
The presence of a magnetic field can make a portion of compressible
fluid less dense than its surroundings, so that it floats upward under the
influence of gravity. This magnetic buoyancy is thought, in fact,
to be the
mechanism by which magnetic flux tubes rise through the Sun's convection
zone and break at the surface in the form of sunspots.
The rate at which these magnetic flux tubes rise is of major interest,
and was once thought to be far too fast, in fact, for the
self-consistency of the whole picture. My own contribution was to show
that the
Sun's rotation would have a major effect on the process, by
drastically
reducing the rate at which the magnetic buoyancy instabilities develop.
I argued, too, that it would
substantially lengthen the time taken for the flux tubes to reach the
surface.
Nature
Vol 277, pp 41-42, 1979
Solar Phys. Vol 62, pp 23-50, 1979