DIRECT MEASUREMENTS OF FLUX TUBE INCLINATIONS IN SOLAR PLAGES

Observations of the full Stokes vector in three spectral lines indicat e that flux tubes in solar plages have an average inclination in the p hotosphere of 14 degrees with respect to the local vertical. Most flux tubes are inclined in the eastwards direction, i.e., opposite to the solar rotation. We have recorded the Stokes vector of the Fe I 5247.1 Angstrom, Fe I 5250.2 Angstrom, and Fe I 5250.7 Angstrom lines in nine different plages with the polarization-free 20 cm Zeiss coronagraph a t the Arosa Astrophysical Observatory of ETH Zurich. The telescope has been modified for solar disk observations. The chosen spectral lines are particularly sensitive to magnetic field strength and temperature. To determine the field strength and geometry of the flux tubes in the observed plages we use an inversion code that numerically solves the radiative transfer equations and derives the emergent Stokes profiles for one-dimensional model atmospheres consisting of a flux tube and it s surrounding non-magnetic atmosphere. Our results confirm earlier ind irect estimates of the inclination of the magnetic fields in plages.