Intense bipolar structures from stratified helical dynamos
by
Dhrubaditya Mitra
→
Europe/Stockholm
122:026
122:026
Description
We perform direct numerical simulations of the equations of
magnetohydrodynamics with external random forcing and in the presence of
gravity. The domain is a divided in two parts, in the bottom layer the
forcing is helical whereas in the top layer the helicity of the forcing is
zero with a smooth transition in the middle. At early times, a large-scale
helical dynamo develops in the bottom layer. At late times the dynamo
saturates, but the vertical magnetic flux continues to develop and rises to
form dynamic bipolar structures at the top, which later dis- appear and
reappear again. Their field strength can exceed three times the
equipartition value of the turbulence. This is the first example of
self-consistent generation of bipolar magnetic structures from a dynamo
simulation.
