Ion storage ring measurements of dielectronic recombination for astrophysically relevant Fe{sup q+} ions

Journal Article · Thu Jun 10 00:00:00 EDT 1999 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.59121· OSTI ID:21205549

Savin, D W; Kahn, S M ^[1]; Badnell, N R ^[2]; Bartsch, T; Brandau, C; Hoffknecht, A; Mueller, A; Schippers, S ^[3]; Chen, M H ^[4]; Grieser, M; Gwinner, G; Linkemann, J; Repnow, R; Saghiri, A A; Schmitt, M; Schwalm, D; Wolf, A ^[5]

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1. Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027 (United States)
2. University of Strathclyde, Glasgow, G4 0NG (United Kingdom)
3. Institut fuer Kernphysik, Strahlenzentrum der Justus-Liebig-Universitaet, D-35392 Giessen (Germany)
4. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
5. Max-Planck-Institut fuer Kernphysik, D-69117 Heidelberg (Germany)

Iron ions provide many valuable plasma diagnostics for cosmic plasmas. The accuracy of these diagnostics, however, often depends on an accurate understanding of the ionization structure of the emitting gas. Dielectronic recombination (DR) is the dominant electron-ion recombination mechanism for most iron ions in cosmic plasmas. Using the heavy-ion storage ring at the Max-Planck-Institute for Nuclear Physics in Heidelberg, Germany, we have measured the low temperature DR rates for Fe{sup q+} where q=15, 17, 18, and 19. These rates are important for photoionized gases which form in the media surrounding active galactic nuclei, X-ray binaries, and cataclysmic variables. Our results demonstrate that commonly used theoretical approximations for calculating low temperature DR rates can easily under- or over-estimate the DR rate by a factor of {approx}2 or more. As essentially all DR rates used for modeling photoionized gases are calculated using these approximations, our results indicate that new DR rates are needed for almost all charge states of cosmically abundant elements. Measurements are underway for other charge states of iron.

• OSTI ID: 21205549
• Journal Information: AIP Conference Proceedings, Vol. 475, Issue 1; Conference: 15.International conference on the application of accelerators in research and industry, Denton, TX (United States), 4-7 Nov 1998; Other Information: DOI: 10.1063/1.59121; (c) 1999 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
CHARGE STATES
COMPUTERIZED SIMULATION
ELECTRON-ION COLLISIONS
HEAVY IONS
IRON IONS
MULTICHARGED IONS
PHOTOIONIZATION
PLASMA DIAGNOSTICS
RECOMBINATION
STORAGE RINGS