3-D Modeling of Thermal Structure in Active Regions on the Solar Surface
Abstract
The thermal structure of a magnetically active region depends on a complicated balance between plasma heating, radiative cooling and the highly anisotropic thermal conduction guided by the magnetic field. It is also affected by plasma convection if siphon flows exist as a result of dynamic imbalance of pressure gradient, gravity and magnetic force. The difficulty of the numerical simulation lies in the wide ranges of density and temperature, separated by a narrow transition region with enormous gradients. Early studies of 1-D models (Mok et. al. 1991) provide a guidance on the thermal structure along individual field lines. A slightly more advanced 2-D model (Mok and Van Hoven 1993) produces a differential emission measure that is remarkably consistent with observations on the quiet sun. Active regions, however, require a 3-D model. We have implemented the necessary thermodynamics into our 3-D MHD code for this study. By starting with a magnetogram of an active region, we first establish an overlying magnetic structure. We then compute the thermal structure in the atmosphere. One of the most poorly understood physical processes in the energy balance is the plasma heating. We have computed the thermal structure based on various heating models and will compare their resulting emission measures. Mok, Schnack, and Van Hoven, 1991, Solar Phys. 132, 95. Mok and Van Hoven, 1993, Solar Phys. 146, 5. Work supported by the Sun Earth Connection Theory Program of NASA.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..SH41A20M
- Keywords:
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- 7509 Corona;
- 7524 Magnetic fields