Here we report on observations of the three-dimensional structure of a sunspot magnetic field from the photosphere to the chromosphere, obtained with the new visible/infrared spectro-polarimeter SPINOR. The observations, interpreted with a non-LTE modeling technique, reveal a surprisingly complex topology with areas of opposite-sign torsion, suggesting that flux-ropes of opposite helicities may coexist together in the same spot.
@article{arxiv.astro-ph/0508688,
title = {The Three-Dimensional Structure of a Sunspot Magnetic Field},
author = {H. Socas-Navarro},
journal= {arXiv preprint arXiv:astro-ph/0508688},
year = {2009}
}