Search

We present a simple one-dimensional iterative kinetic model of the cathode sheath region of high voltage, low-pressure hydrogen hollow cathode discharge. The model's convenience as a supplemental diagnostic tool is demonstrated by determining the most relevant discharge parameters through an analysis of the spectral shape of the hydrogen Balmer alpha line recorded along the axis of a cylindrically symmetrical high voltage low-pressure hollow cathodeglow discharge in hydrogen. Thus, an effectively one-dimensional approach is tested and shown to give satisfactory spectral lines fits with reasonable values for discharge parameters, most notably the gas temperature. [ABSTRACT FROM AUTHOR]

We report the results of optical emission spectroscopy measurements of rotational Trot and translational (gas) temperature of deuterium molecules. The light source was a low-voltage high-pressure hollow cathode (HC) glow discharge with titanium cathode operated in deuterium. The rotational temperature of excited electronic states of D2 was determined from the intensity distribution in the rotational structure of Q-branches of the two Fulcher-α diagonal bands: [v' = v'' = 2] and [v' = v'' = 3]. The population of the excited energy levels, determined from relative line intensities, was used to derive the radial distributions of the temperature of the excited and the ground state of the deuterium molecule. [ABSTRACT FROM AUTHOR]

We report the results of an Ar I and Ne I line shape study in an abnormal glow discharge operating in argon and neon. The spectral lines were observed along the axis of a cylindrical glow discharge parallel (side-on) and perpendicular (end-on) to the cathode surface. The side-on spectra show spectral line shifting and sometimes simultaneous shifting and splitting in the cathode fall region of the glow discharge. The results of the measured line shift with available data for the dc Stark effect are used for measurement of electric field strength in the cathode fall region of the glow discharge. Electron temperatures of 2860 K and 4770 K in the negative glow region of argon and neon discharges, respectively, were determined from the relative intensities of Ar I or Ne I lines using the Boltzmann plot technique. An electron number density of ≈1020 m−3 (±25%) in the negative glow region of the argon discharge was determined from the widths of two plasma-broadened Ar I lines using theoretical Stark broadening data. The end-on recorded line profiles show 10–40% larger half-widths than the side-on recorded line profiles from the negative glow. This effect is a result of the superposition of line emission in the cathode fall region under the influence of the dc Stark effect on the line profile from the negative glow. [ABSTRACT FROM AUTHOR]

A comparative study of the radial intensity distribution of the excessively Doppler broadened hydrogen Hα line in a hollow cathode (HC) glow discharge operated in hydrogen and argon-hydrogen gas mixtures with stainless steel (SS) and titanium (Ti) cathode is reported. The main interest of this work is focused on the dependence of radial distribution upon cathode material and cathode surface composition. The analysis of experimental radial distributions and results obtained from H+↦ metal surface interaction simulation combined with available data for H ↦ metal target interaction explains the difference between SS and Ti cathodes. These results explain also the important role of metal hydrides at the cathode surface for discharge-HC interaction. The influence of the hollow cathode temperature on the radial distribution of the excessively broadened Hα line and on the emission of Ar I and Ar II lines from discharge in argon-hydrogen gas mixture are also investigated. The increase of the excessive Doppler broadened part of the Hα line profile with HC temperature is always detected. The intensity of Ar I and Ar II lines is also used to examine the influence of small admixtures of hydrogen in argon. [ABSTRACT FROM AUTHOR]