A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. I. Theory
Abstract
We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and stereoscopically triangulated coronal loops, or by 3D vector-magnetograph data. The derived NLFFF solutions provide the magnetic field components Bx(x), By(x), Bz(x), the force-free parameter α(x), the electric current density j(x), and are accurate to second-order (of the nonlinear force-free α-parameter). The explicit expressions of a force-free field can easily be applied to modeling or forward-fitting of many coronal phenomena.
- Publication:
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Solar Physics
- Pub Date:
- October 2013
- DOI:
- 10.1007/s11207-012-0069-7
- arXiv:
- arXiv:1207.2780
- Bibcode:
- 2013SoPh..287..323A
- Keywords:
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- Sun: corona;
- Sun: magnetic fields;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Solar Physics (in press), 26 pages, 11 figures