Abstract Details
Laboratory Astrophysics at Z: Stellar Interior Opacities and Photoionization Kinetics
Author: James E. Bailey
Requested Type: Oral Only
Submitted: 2009-04-20 11:26:53
Co-authors: G.A. Rochau, S.B. Hansen, T.J. Nash, P.W. Lake, and D.S. Nielsen (Sandia National Laboratories, Albuquerque, NM, 87185-1196); C.A. Iglesias (University of California, Lawrence Livermore National Laboratory, Livermore, CA, 94550); J. Abdallah Jr. (Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545); J.J. MacFarlane, I. Golovkin, and P. Wang (Prism Computational Sciences, Madison, WI, 53703); R.C. Mancini and I. Hall (University of Nevada, Reno, NV); C. Blancard, Ph. Cosse, G. Faussurier, F. Gilleron, and J.C. Pain (CEA, DAM, DIF, F-91297 Arpajon, France) ; D. Cohen and M. Rosenberg (Swarthmore College, Swarthmore, PA, 19081); A.K. Pradhan, S.N. Nahar, and M. Pinsonneault (Ohio State University, Columbus, Ohio, 43210); D. Arnett and C. Meakin (University of Arizona, Tucson, Arizona, 85721)
Contact Info:
Sandia National Laboratories
P.O. Box 5800
Albuquerque, NM 87185-1
USA
Abstract Text:
Laboratory experiments at Z use high energy density to create plasma conditions similar to extreme astrophysical environments, including stellar interiors and the plasma that surrounds accretion powered objects. The importance of radiation connects these topics, even though the plasmas involved are very different. Understanding stellar interiors requires knowledge of radiation transport in dense, hot, collision-dominated plasma. A Z x-ray source was used to measure iron plasma transmission at 156 eV electron temperature, 2x higher than in prior work. The data provide the first experimental tests of absorption features critical for stellar interior opacity models and may provide insight into whether the present discrepancy between solar models and helioseismology originates in opacity model deficiencies or in some other aspect of the solar model. New experiments reaching higher density and temperature conditions are underway. In contrast, accretion physics requires interpretation of x-ray spectra from lower density photoionization-dominated plasma. Exploiting astrophysical spectra requires a model that connects the observations with the overall picture of the astrophysical object. However, photoionized plasma spectral models are largely untested. Z-pinch radiation was used to create photoionized neon plasmas with photoionization parameter ~ 5-25 erg cm s-1. Comparisons with the data improve x-ray photoionization models and promote more accurate interpretation of spectra acquired with astrophysical observatories. New experiments at the recently upgraded Z facility will be described.
++Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
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