AIP Digital Archive
Electrical Engineering, Measurement and Control Technology
Following charge exchange between fast neutral atoms and impurities, emission from the charge exchange product can take two forms. The first is prompt radiation due to rapid cascading of the excited electron following the charge exchange event. In addition, as a result of electron impact excitation from the ground state before ionization, the impurity can subsequently radiate at the chosen wavelength. Depending on the beam-sightline geometry, plasma density, and species observed, the emission of this "ion plume'' can rival the prompt emission, making it a potentially important consideration for ion temperature and density measurements. Direct measurements of this ion plume radiation after the charge exchange event have been made for He+ ions (n=4–3, 4686 A(ring)) and C5+ ions (n=8–7, 5292 A(ring)). The ratios of plume radiation to prompt charge exchange radiation for these transitions is compared to predictions from modeling, and good agreement is found. This work was supported by U.S. Department of Energy Contract No. DE-AC02-76-CHO-3073.
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