HR: 1330h
AN: P43A-01    [Abstracts]
TI: High-resolution Crystal Spectroscopy of Charge-Exchange Produced K-shell X-ray Emission Lines
AU: * Beiersdorfer, P
EM: beiersdorfer@llnl.gov
AF: Lawrence Livermore National Laboratory, 7000 East Ave, L-260, Livermore, CA 94550 United States
AU: Bitter, M
EM: bitter@pppl.gov
AF: Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08544 United States
AU: Olson, R
EM: olson@umr.edu
AF: University of Missouri-Rolla, Department of Physics, Rolla, MO 65409 United States
AU: Marion, M
EM: marion3@llnl.gov
AF: Lawrence Livermore National Laboratory, 7000 East Ave, L-260, Livermore, CA 94550 United States
AB: Charge-exchange spectral models needed to describe and predict the X-ray emission of cometary and planetary atmospheres interacting with solar wind heavy ions are under development and require laboratory data for guidance. The relative intensity of the four K-shell emission lines in heliumlike ions is particularly uncertain, as the individual lines have not yet been fully resolved in charge-exchange-produced spectra. Using a high-resolution crystal spectrometer, we have measured the charge exchange induced K-shell X-ray emission from Ar¹⁶⁺ following the interaction of Ar¹⁷⁺ ions with fast, 40 keV/amu deuterium atoms. The measurement was performed on the National Spherical Torus Experiment (NSTX). The Ar¹⁷⁺ ions were constituents of the plasma, while deuterium was injected via a 80 keV neutral beam. During the brief, 20 ms neutral beam injection emission from electron-impact collisions ceases, and X-ray line emission is solely due to charge exchange. The measurement fully resolves the resonance, intercombination, and forbidden lines. We have constructed a complete radiative cascade model of Ar¹⁶⁺ that includes electron capture into levels as high as n=29 and all E1, M1, E2, and M2 radiative transitions. We find excellent agreement between the model and the NSTX crystyal spectrum. We will present these findings as well as our predictions of the emission in other spectral bands from the optical and extreme ultraviolet to the soft X-ray region. This work was performed under the auspices of the U.S. DOE by UC-LLNL under contract W-7405-Eng-48, by UMR under contract DE-FG02-84ER53175, and by PPPL under contract DE-AC02-76CHO3073.
DE: 2164 Solar wind plasma
DE: 6060 Radiation and spectra
DE: 6210 Comets
SC: Planetary Sciences [P]
MN: 2005 Joint Assembly