J. Musielok

Calibration of the width of the NI spectral line at 7915.42 Å for electron density determination

Abstract The Stark broadening of a NI spectral line at 7915.42 A has been calibrated for electron density determination of low temperature plasmas. The determined simple formula based on measured FWHM is applicable in the electron density range from 3×1015 to 10 16 cm −3 .

Stark broadening studies of the infrared OI multiplet \rm {3p{\,}^{5}P\hbox{--}3d{\,}^{5}D^{o}}

Experimental line broadening studies of the infrared OI multiplet are reported. Stark broadening parameters, electron-impact widths (w) and shifts (d) as well as asymmetry (A), are determined applying a wall-stabilized high-current arc as the plasma source. Broadening studies are performed in the electron density range 0.8 × 1016–1.4 × 1016 , corresponding to plasma temperatures from 12 000 to 13 800 K. The obtained broadening and shift parameters, normalized to the standard electron density value of 1 × 1016 , are compared with results of calculations reported in a 1974 monograph by Griem.

Experimental Stark broadening studies of the CI transition 3s1P1o − 3p1S0 at 833.5 nm

Experimental Stark broadening studies of the infrared CI transition 3s1P1o − 3p1S0 at 833.5 nm are reported for the first time. A high-current wall-stabilized arc, operated in a mixture of helium, argon, carbon dioxide and hydrogen, was applied as the plasma source. Radiation emitted from homogeneous and optically thin plasma layers was analyzed. Stark broadening studies of the selected CI transition and the hydrogen Balmer β line were performed. As expected from theoretical considerations, the CI line width depends linearly on the electron density of the plasma. Applying theoretical Stark broadening data for the Hgb line, the measured Stark widths of the CI line were calibrated for the purpose of electron density determination in low temperature plasmas.

Measurements and Calculations of Stark Broadening and Shift Parameters of Selected Spectral Transitions of NI

We present new measurements of broadening and shift parameters for 5 NI multiplets from the infrared region of the spectrum. The selected spectra have been excited in a wall‐stabilized high‐current arc operated in a helium‐nitrogen mixture with traces of hydrogen for diagnostic purposes. Primary Stark broadening parameters — the Stark effect constants C4 have been calculated for 13 NI multiplets and compared with results of our new measurements and with other experimental data available in literature.

Experimental investigations of two doubly excited NI multiplets

Experimental Stark-broadening studies of two NI multiplets (1D)3s 2D-(1D)3p 2D° and (1D)3s 2D-(1D)3p 2F° are reported. Measurements were performed using a wall-stabilized arc operated at atmospheric pressure in helium with small amounts of nitrogen and hydrogen. The Stark broadening parameters: the electron impact width (we)and shift (de) have been determined.

Paschen β line shape studies in low-temperature plasmas

Line shape calculations and measurements of the Paschen β line of hydrogen (λ=12818 Å) are reported. Measurements were performed at electron densities of the plasma between 1015 cm-3 and 1016 cm-3. A wall-stabilized arc operated at atmospheric pressure in a helium-hydrogen gas mixture was applied as the excitation source. The radiation of the plasma, originating from nearly homogeneous plasma layers, in the end-on direction, was analyzed. A grating spectrometer equipped with a CCD detector was used for the radiation detection. The measured line profiles are compared with results of available experimental and theoretical Stark broadening data e.g. based on simulation techniques, applied also in our calculations.