Broad ion energy distributions in helicon wave-coupled helium plasma
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Author(s)
Woller, Kevin Benjamin
Whyte, Dennis G
Wright, Graham
Date Issued
May 2017
Journal
Physics of Plasmas
Publisher
American Institute of Physics (AIP)
Citation
Woller, K. B. et al. “Broad Ion Energy Distributions in Helicon Wave-Coupled Helium Plasma.” Physics of Plasmas 24, 5 (May 2017): 053513 © 2017 Author(s)
Version
Author's final manuscript
Abstract
Helium ion energy distributions were measured in helicon wave-coupled plasmas of the dynamics of ion implantation and sputtering of surface experiment using a retarding field energy analyzer. The shape of the energy distribution is a double-peak, characteristic of radiofrequency plasma potential modulation. The broad distribution is located within a radius of 0.8 cm, while the quartz tube of the plasma source has an inner radius of 2.2 cm. The ion energy distribution rapidly changes from a double-peak to a single peak in the radius range of 0.7-0.9 cm. The average ion energy is approximately uniform across the plasma column including the double-peak and single peak regions. The widths of the broad distribution, ΔE, in the wave-coupled mode are large compared to the time-averaged ion energy, 〈E〉. On the axis (r = 0), ΔE/ 〈E〉 ≲ 3.4, and at a radius near the edge of the plasma column (r = 2.2 cm), ΔE/ 〈E〉 ∼ 1.2. The discharge parameter space is scanned to investigate the effects of the magnetic field, input power, and chamber fill pressure on the wave-coupled mode that exhibits the sharp radial variation in the ion energy distribution.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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DOI of Published Version
https://doi.org/10.1063/1.4983315
