Active Regions and the Global Magnetic Field of the Sun
Abstract
The Sun follows an 11 year activity cycle, over which the global magnetic field begins highly dipolar, and becomes more complex at cycle maximum, until reverting back to a dipole state, but with reversed polarity. Many magnetic structures of varying complexity (active regions) are observed to emerge, evolve, and decay over the cycle. Beyond location and orientation, the dependence of active region magnetic properties on the phase of the solar cycle is not well known. Here, we use automated feature detection methods to detect and characterize thousands of active region detections and statistically investigate their physical properties. We find that the mean size and flux of magnetic features on the solar disk is dependent on the phase of the cycle. We establish a direct connection between the spatial distribution of active regions on the solar disk and the configuration of the global solar magnetic field by investigating the polarity imbalance of feature magnetic flux. Using a global potential field source surface model, we find that the shape of the global field is strongly dependent on the large scale distribution of imbalanced flux.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMSH43B1940H
- Keywords:
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- 7524 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Magnetic fields;
- 7529 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Photosphere;
- 7536 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar activity cycle