Can We Use STEREO/EUVI to Improve Boundary Conditions for Magnetic Modeling?
Abstract
The STEREO mission provides a unique opportunity to observe active region loops simultaneously from two different vantage points in space. Using the stereoscopic data, we can triangulate 3D coordinates for active region loops and use them to perform quantitative comparisons between observed loop geometries and theoretical magnetic field models. These comparisons provide some insight into the validity of magnetic field models, but recent work (DeRosa et al. 2009, Sandman et al. 2009) has shown that potential and non-potential models yield equally poor agreement with observed loop structures. In order to improve the results of magnetic modeling we must resolve the discrepancy between the typically force-free domain (the corona) and non-force-free boundary condition (the photosphere or chromosphere). We seek to address this discrepancy by "correcting” the boundary condition using observational constraints. The magnetic field in the low corona cannot currently be mapped directly, but using STEREO 3D loop coordinates we can constrain the orientation of the magnetic field in the low corona. In a previous study we measured the misalignment angles between model magnetic fields and observed coronal loops in three active regions, as observed with STEREO/EUVI on April 30, May 9, and May 19, 2007. We now use these misalignment angles to modify the magnetogram input to the magnetic field model. The resulting model field has minimal misalignment with the observed coronal loops near the base of the corona, allowing for a more realistic field extrapolation.
- Publication:
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AAS/Solar Physics Division Meeting #40
- Pub Date:
- May 2009
- Bibcode:
- 2009SPD....40.1220S