Doppler-Zeeman mapping of magnetic CP stars: solution of the inverse   problem simultaneously from the Stokes I, V, Q and U parameters
  An efficient method has been developed for solving the inverse problem of Doppler-Zeeman mapping of magnetic, chemically peculiar stars. A regularized iteration method is used to simultaneously solve the integral equations for the Stokes I, V, Q and U parameters. The validity of analytical fits to the local profiles of the Stokes parameters is substantiated. The algorithm had been tested on models and makes it possible to obtain simultaneously, from the observed Stokes profiles, a map of the distribution of a chemical element and the parameters of an arbitrarily shifted magnetic dipole. 
D.V. Vasil'chenko, V.V. Stepanov (Dep. Comp. Math. & Cyb., Moscow),   V.L. Khokhlova (Inst. Astron., Moscow)