Speaker
Bob Stein
(Michigan State University)
Description
Simulation results will be shown for two cases: weak,
non-buoyant and strong, buoyant uniform, untwisted,
horizontal magnetic fields advected into the computational
domain by inflows at 20 Mm depth. Convection both shreds
the magnetic field into many thin fibrils as well as keeps
the larger-scale structure confined within the inflow
supergranule cell. Convective upflows and downflows bend
the field into serpentine loops. Magnetic field first
emerges as horizontal field over granules with vertical legs
in the intergranular lanes and elongates the granules in the
field direction. Because of the fibril substructure, the
field first emerges in a mixed polarity, "pepper and salt"
pattern. As the underlying, large-scale loop emerges, the
opposite polarity components at the surface stream into
uni-polar flux concentrations at its nearly vertical legs.
The three most obvious differences between the weak and
strong field cases are: first, the buoyant loop emerges much
more quickly (1 day vs 2 days from 20 Mm); second, the weak
field does not distort the supergranule-scale convective
cells while the strong field enlarges the cells in the field
direction which results in the opposity polarit legs
spreading apart; third, the field is more horizontal
surrounding the leg remaining behind in the strong field case.
Primary author
Bob Stein
(Michigan State University)
Co-author
Aake Nordlund
