Vacuum ultraviolet spectroscopic measurements of opacity on hydrogen resonance lines in the Maryland Centrifugal Experiment (MCX)
Abstract
Measurements of the shapes and relative intensities of n-to-1 Lyman-series vacuum-uv spectral lines from hydrogen in MCX are crucial to an understanding of the role of opacity in radiative transfer modeling. One goal is to measure decreasing line peak-to-wing intensity ratios for opacity and relative intensities along the series with increasing depth of view into the plasma. This represents somewhat an extension of previous MCX measurements ^1 of rotation velocity and atom temperature using Doppler shifts and widths, respectively, of n-to-2 Balmer lines in the visible. To date, line width measurements up to n=5 indicate opacity on each to a some degree, which suggests a neutral hydrogen density in the 10^14 cm-3 range consistent with recent electron density measurements using interferometry^2. Total relative intensities along the series decrease less rapidly than expected. They may be used to determine an electron temperature for comparison with the Balmer series, which currently indicate a value of ∼1 eV, lower than an atom temperature of 5-10 eV^1. ^1J. Ghosh, et al., Physics of Plasmas, v. 11, 3813 (2004). ^2C. Teodorescu, et al., abstract this conference.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2004
- Bibcode:
- 2004APS..DPPBP1125G