A possible diagnostic method for magnetic field and velocity gradients in sunspots

We present a diagnostic method for detecting magnetic field gradients and velocity gradients in sunspots through the analysis of Stokes parameters profiles in magnetoactive lines. On one hand, the method is based on the concept of response functions for the Stokes profiles introduced by Landi Degl'Innocenti and Landi Degl'Innocenti (1977); on the other hand, it takes advantage of the diagnostic content of the residuals between observed Stokes profiles and best-fit Unno-profiles. The analysis of synthesis profiles obtained for the line 6302.502 FeI forming in the Sunspot Sunspot Model (Avrett, 1981) suggests that the method could actually be promising, at least if the dependence of the magnetic field vector on optical depth is sufficiently simple.