(a) The helicon source (HELIX)-diffusion chamber (LEIA) system. LP measurement were performed at locations A and C ; LIF measurements were performed at locations B and C . (b) Magnetic field profile and magnitude, and magnetic field gradient vs axial position over the entire length of HELIX-LEIA system. (c) Contours of constant magnetic flux showing the increased divergence that results when the magnetic field in the expansion region decreases from 70 G (dashed line) to 14 G (solid line) for a constant source field of 600 G.
Partial energy level diagrams for argon and xenon neutrals and the transitions used for OES investigations; the ionization levels are shown by horizontal dashed lines; and are metastable states; , , and are radiative states (adapted from Refs. 31 and 42).
Electron energy probability functions for (a) pure argon plasma and (b) pure xenon plasma.
Effective electron temperature and electron density obtained from experimentally obtained eepfs as a function of Ar/Xe composition: (a) at in HELIX, ; and (b) on the axis of LEIA, . The dashed lines are exponential and linear fits for electron temperature and electron density, respectively. Source plasma parameters: , , , and .
(a) Observed emission line intensities from Ar I (811.75 nm) and Xe I (823.39 nm) lines in HELIX at vs xenon fraction; the emission intensities values are normalized to the corresponding pure gases values. The argon emission line intensity was indistinguishable from the background for xenon fractions larger than 80%. (b) Neutral species densities in the plasma as computed from the argon and xenon line intensities ratios: open symbols, Corona model without metastable contribution; full symbols, Corona model with metastable contribution. Solid lines, computed values from the gas flow data.
(a) Computed ion densities in HELIX as a function of xenon fraction; and (b) plasma potential in HELIX at (dark circles) and in LEIA at (light circles) vs xenon fraction.
(a) Electron temperature (circles) and electron density (squares) inferred from Langmuir probe measurements in HELIX plasmas at as function of helium fraction; and (b) normalized partial ion densities vs helium fraction in HELIX. Operating conditions: , , , and .
Article metrics loading...
Full text loading...