Properties of solar pores

Abstract

We present the results of an extensive investigation of the properties of solar pores. Spectra of all 4 Stokes parameters of several magnetic sensitive absorption lines as well as Stokes I only spectra of lines with low or vanishing Landéfactor have been observed. An inversion code based on the Levenberg-Marquardt algorithm was written, incorporating the full radiative transfer equations. This code adapts a set of parameters that are used to represent the magnetic and thermodynamic state of the atmosphere to best-fit a set of observed lineprofiles. The results show that the value of all relevant parameters are intimately related to the size of the pores, therewith confirming the role of solar pores as a link between (bright) magnetic flux tubes and sunspots. In particular the inclination of themagnetic field lines at the outer rim of a pore, which is affectedby the vertical field gradient, seems to put an upper limit onthe diameter of pores where the inclination reaches a value thatmight trigger the formation of a penumbra.