Simulating exploding granules and mesogranular flows

Abstract

Cellular convective motion at the solar surface can be simulated by a suitable distribution of axisymmetric sources /1/. With this model we represent randomly distributed exploding granules or mesogranules. The effect of a given velocity field on the magnetic field is modelled by inserting test particles (“corks”) and following their resultant motions. An important question raised by the observations is whether mesogranular flows are generated entirely by exploding granules which recur in approximately the same location or whether there is a persistent underlying circulation. Our model calculations suggest that a combination of systematic cellular motion on a mesogranular scale and recurrent exploding granules located near the mesogranular centers is compatible with observed magnetic structures. We also generate randomly-distributed exploders not tethered to mesogranular sites, and the resulting cork patterns do not resemble those observed on the solar surface. Finally we introduce a large-scale persistent supergranular flow which transports the mesogranules and exploders towards the supergranular network and obtain patterns not unlike those seen on the Sun.