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Title: Ion storage ring measurements of dielectronic recombination for astrophysically relevant Feq+ ions

Abstract

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.

Authors:
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Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
15005858
Report Number(s):
UCRL-JC-139163
TRN: US0400225
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Applications of Accelerators in Research and Industry, Denton, TX (US), 11/04/1998--11/07/1998; Other Information: PBD: 6 Jun 2000
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCELERATORS; ACCURACY; CHARGE STATES; FEDERAL REPUBLIC OF GERMANY; GASES; IONIZATION; IRON; IRON IONS; NUCLEAR PHYSICS; NUCLEI; PLASMA DIAGNOSTICS; RECOMBINATION; SIMULATION; STORAGE RINGS

Citation Formats

Savin, D W, Badnell, N R, Bartsch, T, Brandau, C, Chen, M H, Grieser, M, Gwinner, G, Hoffknecht, A, Kahn, S M, Linkemann, J, Muller, A, Repnow, R, Saghiri, A A, Schippers, S, Schmitt, M, Schwalm, D, and Wolf, A. Ion storage ring measurements of dielectronic recombination for astrophysically relevant Feq+ ions. United States: N. p., 2000. Web.
Savin, D W, Badnell, N R, Bartsch, T, Brandau, C, Chen, M H, Grieser, M, Gwinner, G, Hoffknecht, A, Kahn, S M, Linkemann, J, Muller, A, Repnow, R, Saghiri, A A, Schippers, S, Schmitt, M, Schwalm, D, & Wolf, A. Ion storage ring measurements of dielectronic recombination for astrophysically relevant Feq+ ions. United States.
Savin, D W, Badnell, N R, Bartsch, T, Brandau, C, Chen, M H, Grieser, M, Gwinner, G, Hoffknecht, A, Kahn, S M, Linkemann, J, Muller, A, Repnow, R, Saghiri, A A, Schippers, S, Schmitt, M, Schwalm, D, and Wolf, A. Tue . "Ion storage ring measurements of dielectronic recombination for astrophysically relevant Feq+ ions". United States. https://www.osti.gov/servlets/purl/15005858.
@article{osti_15005858,
title = {Ion storage ring measurements of dielectronic recombination for astrophysically relevant Feq+ ions},
author = {Savin, D W and Badnell, N R and Bartsch, T and Brandau, C and Chen, M H and Grieser, M and Gwinner, G and Hoffknecht, A and Kahn, S M and Linkemann, J and Muller, A and Repnow, R and Saghiri, A A and Schippers, S and Schmitt, M and Schwalm, D and Wolf, A},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {6}
}

Conference:
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