Physics Commons^™

Observations Of Neutral Depletion And Plasma Acceleration In A Flowing High-Power Argon Helicon Plasma, C. Mark Denning, Matt Wiebold, John E. Scharer

Physics Faculty Publications

Neutral depletion effects are observed in a steady-state flowing argon helicon plasma with a magnetic nozzle for high rf input powers (up to 3 kW). Noninvasive diagnostics including 105 GHz microwave interferometry and optical spectroscopy with collisional-radiative modeling are used to measure the electron density (n_e), electron temperature (T_e), and neutral density (n_n). A region of weak neutral depletion is observed upstream of the antenna where increasing rf power leads to increased electron density (up to n_e = 1.6×10¹³ cm^-3) while T_e remains essentially constant and …