On the Stability of Active Regions and Sunspots
Abstract
Recent helioseismic measurements of large-scale subsurface flows indicate that systematic horizontal inflows near the photosphere surround many active regions. Such active-region inflows are likely to impede the dispersal of magnetic flux into the surrounding network and thus can influence larger-scale and longer-term patterns and evolution of the surface magnetic field throughout the course of a solar activity cycle. We present results of numerical simulations of compressible magnetoconvection in which an initial unipolar magnetic field undergoes evolution resulting from convectively driven motions. Inflows surrounding regions of concentrated magnetic flux are driven by reducing the surface temperature as a function of local magnetic flux. We find flow patterns that are consistent with observations of those observed around active regions and sunspots.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2008
- DOI:
- 10.1086/591736
- Bibcode:
- 2008ApJ...684L.123H
- Keywords:
-
- Sun: atmospheric motions;
- Sun: faculae;
- plages;
- Sun: magnetic fields;
- sunspots