STOKES PROFILES INVERSION TECHNIQUES

Inversion techniques of the radiative transfer equation for polarized light are presented as one of the best current procedures to infer the vector magnetic field, as well as other quantities governing the phys ical state of the atmospheric layers that photons are coming from. Sev eral characteristics of the various available inversion procedures are pointed out. They are mostly based on the diagnostic contents of the spectral lines as well as on the main hypotheses assumed in these proc edures. In particular, the role of gradients in the atmospheric quanti ties is emphasized as of paramount importance in any diagnostic analys is and, hence, in any interpretation of inversion results.