Advances in helioseismology provide new knowledge about the origin
of solar magnetic activity. The key questions addressed by
helioseismology are: what is the physical mechanism of the solar
dynamo, how deep inside the Sun are the magnetic fields generated,
how are they transported to the surface and form sunspots? Direct
helioseismic signatures of the internal magnetic fields are weak and
difficult to detect. Therefore, most of the information comes from
observations of dynamical effects caused by the magnetic fields. I
review results of recent helioseismic observations of the
magnetohydrodynamics of the solar interior on various scales,
including global dynamics associated with the dynamo processes,
formation of sunspots and active regions, and magnetic energy
release.