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Measurements of the Spectral Light Emission from Decaying High Pressure Helium Plasmas

Abstract

The rate of electron density decay has been determined in a helium pulsed discharge plasma at pressures ranging from 100 to 600 Torr, primarily during the early afterglow where the electron density is from 1019 to 2 x 1017/m3. Measurements of the electrical conductivity and the absolute intensity of the light emission were made. The effective recombination rate coefficient was found to increase faster than linearly with gas pressure. The total photon emission rate was significantly lower than the effective recombination rate. Below 400 Torr pressure the afterglow was dominated by He-bands, which were related to the recombination of He{sub 2+} and He{sub 3+} ions. At higher pressures the appearance of intense lines originating from the atomic n = 3 and 23 P states is proposed to result from the He{sub 4+} recombination. Absorption measurements of the atomic metastable concentration gave evidence for recombination directly into the 23 S state. The concentration of molecular metastables was surprisingly low. The light emission had a Techi dependence, with 0 < chi < 0.35 for the intense atomic lines and 0.78 < chi < 1.10 for the molecular bands
Publication Date:
Apr 15, 1971
Product Type:
Technical Report
Report Number:
AE-418
Resource Relation:
Other Information: 19 refs., 14 figs., 2 tabs.
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HELIUM; PLASMA; AFTERGLOW; ELECTRON DENSITY; PRESSURE RANGE KILO PA; PHOTON EMISSION; ELECTRIC CONDUCTIVITY
OSTI ID:
922477
Research Organizations:
AB Atomenergi, Nykoeping (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
TRN: SE0808022
Availability:
Commercial reproduction prohibited; OSTI as DE00922477
Submitting Site:
SWDN
Size:
52 pages
Announcement Date:
Jan 28, 2008

Citation Formats

Stevefelt, J, and Johansson, J. Measurements of the Spectral Light Emission from Decaying High Pressure Helium Plasmas. Sweden: N. p., 1971. Web.
Stevefelt, J, & Johansson, J. Measurements of the Spectral Light Emission from Decaying High Pressure Helium Plasmas. Sweden.
Stevefelt, J, and Johansson, J. 1971. "Measurements of the Spectral Light Emission from Decaying High Pressure Helium Plasmas." Sweden.
@misc{etde_922477,
title = {Measurements of the Spectral Light Emission from Decaying High Pressure Helium Plasmas}
author = {Stevefelt, J, and Johansson, J}
abstractNote = {The rate of electron density decay has been determined in a helium pulsed discharge plasma at pressures ranging from 100 to 600 Torr, primarily during the early afterglow where the electron density is from 1019 to 2 x 1017/m3. Measurements of the electrical conductivity and the absolute intensity of the light emission were made. The effective recombination rate coefficient was found to increase faster than linearly with gas pressure. The total photon emission rate was significantly lower than the effective recombination rate. Below 400 Torr pressure the afterglow was dominated by He-bands, which were related to the recombination of He{sub 2+} and He{sub 3+} ions. At higher pressures the appearance of intense lines originating from the atomic n = 3 and 23 P states is proposed to result from the He{sub 4+} recombination. Absorption measurements of the atomic metastable concentration gave evidence for recombination directly into the 23 S state. The concentration of molecular metastables was surprisingly low. The light emission had a Techi dependence, with 0 < chi < 0.35 for the intense atomic lines and 0.78 < chi < 1.10 for the molecular bands}
place = {Sweden}
year = {1971}
month = {Apr}
}