R. Kobilarov

Deconvolution of plasma broadened non-hydrogenic neutral atom lines

Abstract A method for the deconvolution of non-hydrogenic neutral atom lines using Marquardt–Levenberg algorithm is presented. Algorithm for application of this method is also described. The application of this method to isolated and overlapping neutral argon lines is given as an example.

Simple method for deconvolution of a Gaussian and a plasma broadened spectral line profile jA,R(χ)

Abstract Computation of the convolution integral of a Gaussian and the Stark-broadened jA,R(χ) profile has been carried out and the results are expressed in a form suitable for the analysis of spectral line profiles.

STARK WIDTH AND SHIFT TEMPERATURE DEPENDENCE OF THE AR I 425.9 NM LINE

Abstract We report measured Stark widths and shifts of the neutral argon 425.9 nm line. A wall stabilized arc is used as a plasma source. Electron densities of 0.5 − 3.5 × 1022 m−3 are determined from the width of the Hβ line and electron temperatures of 9000-11,000 K are deduced from plasma composition data. Measured Stark widths and shifts are systematically smaller than semi-classical theoretical results. Comparison of the experimental Stark widths and shifts with theoretical data shows gradual increase of the discrepancy with temperature. This is more distinctive in the case of shifts.

Measurement of the shock front velocity produced in a T-tube

A set of shock front velocity measurements is described in this paper. The shock waves were produced in a small electromagnetically driven shock T-tube. Most of the measurements were performed in hydrogen. The shock front velocity measurements in other gases and the velocity of the gas behind the shock front were also analyzed, as well as the velocity dependence on applied input energy. Some measurements with an applied external magnetic field were also performed. The used method of shock front velocity is simple and was shown to be very reliable. Measured values were compared with the calculated ones for the incident and reflected shock waves.

Influence of a d.c. magnetic field on the HeI 447.1 nm line in pure helium plasmas

Abstract The HeI 4471 A line with its forbidden component has been studied experimentally in pure helium plasmas in the presence and in the absence of a magnetic field with a flux density of 0.5 T. Profiles were recorded parallel and perpendicularly to the magnetic field lines for an electron-density range from 4×1022 to 9.2×1022m-3 and a temperature range between 20,000 and 30,000 K. The magnetic field influence only the peak separation between the allowed and forbidden components of the line.

Measurement and temporal behaviour analysis of the plasma–glass boundary layer in a T-tube

Refraction of a laser beam by a flat boundary layer between a plasma and a glass plate was measured and the time development of the layer was analysed. Results of the analysis for the plasma produced in a small T-tube show that the boundary layer thickness increases with time faster than linearly. The boundary layer is negligibly thin during the first 3 µs after the reflected shock front has passed the point of observation. This means that a relatively fast collapse due to cooling through the boundary layer occurs in the second part of the reflected plasma lifetime.

On The Stark Shift of Ar II 472.68 nm Spectral Line

The Stark shift of Ar II 472.68 nm (transition 4s2P − 4p2D°) spectral lines emitted from T‐tube plasmas was considered. The electron density ranged from (1.63–2.2)⋅1023 m−3 and was determined using laser interferometry. The plasma temperature, derived from the Gaussian part of recorded line profiles was found to be in the range (15000–43300) K. Experimental shifts were compared to theoretical values obtained from the semiempirical formula [M. S. Dimitrijevic and N. Konjevic, J. Quant. Spectrosc. Radiat. Transfer 24, 451 (1980)]. This comparison showed good agreement between experimental results and theory.