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Title: Broad ion energy distributions in helicon wave-coupled helium plasma

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. In conclusion, 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.
Authors:
ORCiD logo [1] ;  [1] ;  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Grant/Contract Number:
FC02-99ER54512; SC00-02060
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1466016
Alternate Identifier(s):
OSTI ID: 1361886

Woller, K. B., Whyte, D. G., and Wright, G. M.. Broad ion energy distributions in helicon wave-coupled helium plasma. United States: N. p., Web. doi:10.1063/1.4983315.
Woller, K. B., Whyte, D. G., & Wright, G. M.. Broad ion energy distributions in helicon wave-coupled helium plasma. United States. doi:10.1063/1.4983315.
Woller, K. B., Whyte, D. G., and Wright, G. M.. 2017. "Broad ion energy distributions in helicon wave-coupled helium plasma". United States. doi:10.1063/1.4983315. https://www.osti.gov/servlets/purl/1466016.
@article{osti_1466016,
title = {Broad ion energy distributions in helicon wave-coupled helium plasma},
author = {Woller, K. B. and Whyte, D. G. and Wright, G. M.},
abstractNote = {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. In conclusion, 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.},
doi = {10.1063/1.4983315},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {2017},
month = {5}
}