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A: Fachverband Atomphysik
A 4: Electron Scattering and Recombination
A 4.5: Talk
Monday, March 2, 2009, 15:45–16:00, VMP 6 HS-E
Dielectronic recombination by excitation within the n=3 shell for iron ions in astrophysical plasmas — •Michael Lestinsky1,2, Nigel R. Badnell3, Dietrich Bernhardt4, Manfred Grieser2, Jens Hoffmann2, Dragan Lukic1,5, Alfred Müller4, Dmitry Orlov2, Roland Repnow2, Eike W. Schmidt4, Michael Schnell2, Stefan Schippers4, Deyang Yu4,6, Andreas Wolf2, and Daniel W. Savin1 — 1Columbia University, New York — 2Max-Planck-Institut für Kernphysik, Heidelberg — 3Department of Physics, University Strathclyde, Glasgow — 4Institut für Atom- und Molekülphysik, Justus-Liebig-Universität, Gießen — 5Institute of Physics, Belgrade — 6Institute of Modern Physics, Lanzhou
Line emission and absorption from M-shell iron ions are observed in a wide range of cosmic plasmas. Interpreting these spectroscopic data requires an accurate understanding of the underlying charge balance distribution. Dielectronic recombination (DR) is the dominant electron-ion recombination mechanism for most atomic ions in astrophysical plasmas. We are in the process of carrying out a series of DR measurements for M-shell iron ions at the TSR ion storage ring. Here we compare some of our recent results with previously recommended DR data and recent state-of-the-art results. We find significant deviations between theory and experiment at collision energies from 0 to ∼ 50 eV. This range includes all cosmically relevant resonances for these ions. From our experimental data we derive plasma recombination rate coefficients for photoionized and collisionally ionized plasmas and recommend their inclusion into astrophysical codes.