Vector magnetic field measurements along a cooled stereo-imaged coronal loop

Using a unique combination of spectropolarimetry and stereoscopy, we infer and compare the vector magnetic field structure and three-dimensional morphology of an individuated coronal loop structure undergoing a thermal instability. We analyze spectropolarimetric data of the He I lambda 10830 triplet (1s2s S-3 - 1s2p P-3(2,1,0)) obtained at the Dunn Solar Telescope with the Facility Infrared Spectropolarimeter on 2011 September 19.

Cool coronal loops are identified by their prominent drainage signatures in the He I data (redshifts up to 185 km s(-1)). Extinction of EUV background radiation along these loops is observed by both the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the Extreme Ultraviolet Imager on board spacecraft A of the Solar Terrestrial Relations Observatory, and is used to stereoscopically triangulate the loop geometry up to heights of 70Mm (0.1R(Sun)) above the solar surface.