Polarization properties of dielectronic satellite lines in the K-shell x-ray spectra of B-like Fe XXII

We report the results of a combined theoretical and experimental study of B -like dielectronic recombination satellite lines excited by an electron bea m. Polarization sensitive spectra were accumulated at the Lawrence Livermor e electron beam ion trap facility. Three beam energies were chosen in the r egion of maximum B-like Pe satellite emission. At each energy, spectra were obtained using two LiF crystals of differing polarization sensitivities. P olarization-dependent spectra have been calculated using the degree of pola rization of single lines computed with a photon density matrix formalism. T he agreement between the experiment and theory is very good. Two spectral f eatures were observed to have polarizations that were particularly sensitiv e to the electron beam energy. Spectral features with this property are can didates as diagnostics of energy and direction of electron beams in plasmas .