Poster abstract details
The three-dimensional structure of the magnetic field of a sunspot
Abstract
Spectro-polarimetric observations in several spectral lines allow to determine the height variation of the magnetic field of a sunspot throughout the solar photosphere. The full Stokes-vector is measured with high spatial resolution. From these data we derive the magnetic field vector. The magnetic field strength decreases with height in the spot, even in the outer penumbra where some other authors report the opposite. The value of this ecrease
depends on the exact position in the spot. Values vary between 0.5 and 2.2 G\,km$^{-1}$ when they are
determined from an iron and a silicon line in the near infrared. The magnetic field is less inclined in the higher layers. Once the magnetic vector field is known, it is easy to determine current densities and helicities. Current densities exhibit a radial structure in the penumbra. They have a potential to serve as diagnostic tools to understand the penumbra with the spatial resolution of the upcoming telescopes. The mean helicity is negative, as expected for a spot in the northern hemisphere, but there are locations inside the spot with positive helicity.
depends on the exact position in the spot. Values vary between 0.5 and 2.2 G\,km$^{-1}$ when they are
determined from an iron and a silicon line in the near infrared. The magnetic field is less inclined in the higher layers. Once the magnetic vector field is known, it is easy to determine current densities and helicities. Current densities exhibit a radial structure in the penumbra. They have a potential to serve as diagnostic tools to understand the penumbra with the spatial resolution of the upcoming telescopes. The mean helicity is negative, as expected for a spot in the northern hemisphere, but there are locations inside the spot with positive helicity.