Helicon normal modes in Proto-MPEX

• Published in: Plasma sources science & technology Vol. 27; no. 5; p. 55016
• Main Authors: Piotrowicz, P A, Caneses, J F, Green, D L, Goulding, R H, Lau, C, Caughman, J B O, Rapp, J, Ruzic, D N
• Format: Journal Article
• Language: English
• Published: United States IOP Publishing 22.05.2018
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; deuterium; full wave simulation; helicon source; MPEX; plasma source; plasma waves
• ISSN: 1361-6595; 1361-6595
• DOI: 10.1088/1361-6595/aabd62

Here, the Proto-MPEX helicon source has been operating in a high electron density 'helicon-mode'. Establishing plasma densities and magnetic field strengths under the antenna that allow for the formation of normal modes of the fast-wave are believed to be responsible for the 'helicon-mode'. A 2D finite-element full-wave model of the helicon antenna on Proto-MPEX is used to identify the fast-wave normal modes responsible for the steady-state electron density profile produced by the source. We also show through the simulation that in the regions of operation in which core power deposition is maximum the slow-wave does not deposit significant power besides directly under the antenna. In the case of a simulation where a normal mode is not excited significant edge power is deposited in the mirror region.