Population of excited He states (3< or =n< or =8) by dielectronic He/sup +/ recombination in a dc hollow-cathode discharge
The contribution of dielectronic recombination to the population of radiative He I states (3< or =n< or =8) in a He dc hollow-cathode discharge of 4-cm length and 2-cm diameter is determined in the discharge pressure range 0.6--4.0 Torr and at discharge current values of 10, 13, 16, 19, 22, and 25 mA by radial sampling of the emitted line radiation and the ion densities. In addition, the afterglow phase of the same discharge is explored as to the radial and time dependence of line radiation intensity and ion density. In the active phase at low density (2 Torr) and at higher pressure but at too low a discharge current (below 12 mA) all the radiation is due to electron impact excitation of the He states. Only at a pressure of about 4 Torr and a discharge current above 20 mA does recombination play a significant role in populating radiative He I states on the axis of the discharge. The radial dependence of the He II radiation shows the geometric density increase of the very fast unscattered electrons having the full sheath energy. Both results are relevant for hollow-cathode-laser development.
- Research Organization:
- Institut fuer Experimentalphysik der Leopold-Franzens-Universitaet, A-6020 Innsbruck, Austria
- OSTI ID:
- 6635661
- Journal Information:
- Phys. Rev., A; (United States), Vol. 23:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HELIUM IONS
EMISSION SPECTRA
EXCITED STATES
RECOMBINATION
ELECTRIC DISCHARGES
ELECTRONS
HOLLOW CATHODES
LOW PRESSURE
PLASMA DENSITY
PRESSURE DEPENDENCE
CATHODES
CHARGED PARTICLES
ELECTRODES
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
IONS
LEPTONS
SPECTRA
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory