Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Neutral argon density profile determination by comparison of spectroscopic measurements and a collisional-radiative model (invited)

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.2219440· OSTI ID:20861334
;  [1]
  1. Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)
Neutral atoms play important roles in non-fully-ionized plasmas. In helicon sources, neutral pumping and neutral damping of waves are poorly understood. Measurement of the spatial distribution of neutral atoms is possible with spectroscopic diagnostics such as laser-induced fluorescence (LIF) and passive emission spectroscopy. However, these measurements typically apply to an excited neutral atom state, rather than the entire neutral population. With a collisional-radiative (CR) model employing Langmuir probe measured electron parameters in argon helicon source plasmas, we have reproduced LIF and emission spectroscopy measured radial profiles for three excited neutral states. The CR model indicates a neutral depletion on axis of at least 60%. Simple calculations based on measured edge neutral pressures and peak plasma densities significantly underestimate the degree of ionization in the core of the helicon plasma.
OSTI ID:
20861334
Journal Information:
Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 77; ISSN 0034-6748; ISSN RSINAK
Country of Publication:
United States
Language:
English