Stevan Djenize

Ion contribution to the astrophysical important 447.15, 587.56 and 667.82 nm He I spectral lines broadening

Characteristics of the astrophysical important Stark broadened 447.15 nm, 587.56 nm and 667.82 nm Hei spectral line profiles have been measured at electron densities between 0.310 22 and 8.210 22 m 3 and electron temperatures between 8000 and 33 000 K in plasmas created in five various discharge conditions using a linear, low-pressure, pulsed arc as an optically thin plasma source operated in a helium-nitrogen-oxygen gas mixture. On the basis of the observed asymmetry of the line profiles we have obtained their ion broadening parameters (A) caused by influence of the ion microfield on the line broadening mechanism and also the influence of the ion dynamic eect (D) on the line shape. Our A and D parameters represent the first data obtained experimentally by the use of the line profile deconvolution procedure. We have found stronger influence of the ion contribution to these Hei line profiles than the semiclassical theoretical approximation provides. This can be important for some astrophysical plasma modeling or diagnostics.

Stark broadening parameters in C II, C III and C IV spectra

Stark widths and shifts of nine singly charged (C II), one doubly charged (C III) and two triply charged (C IV) prominent carbon spectral lines, have been measured at electron temperatures between 13 800 and 20 500 K and electron densities between 0.91×1023 and 1.96×1023 m-3, using a linear low-pressure pulsed arc, as an optically thin plasma source, operated in CO2. Measured Stark broadening parameters have been compared with the existing experimental and theoretical data.

Ion contribution to the prominent Ne I, Ar I and Kr I spectral line broadening

On the basis of the observed asymmetry of the measured spectral line profiles we have obtained the ion contribution to the Ne (26 lines), Ar I (19 lines) and Kr I (20 lines) spectral line broadening due to the quasi-static ion approximation and ion-dynamical effects. The ion broadening parameters (A) and the ion dynamic coefficients (D) have been obtained directly by the use of our line deconvolution procedure which allows the determination of the basic physical properties that characterize the line profile and also the relevant plasma parameters. We are the first to publish experimental data, viz. D and A values for the Ne I, Ar I and Kr I lines. The 26 Ne I, 6 Ar I and 9 Kr I A values are the first measured data and many of them are the first published data in this field. We have found clear evidence of the quasi-static ion and ion-dynamical effects on the investigated line shapes; they play a much more important role than the approaches based on semiclassical theory provide, especially in the case of the Ne spectral lines. This is of importance for astrophysical plasma modeling and diagnostics.

Astrophysical plasma diagnostics through analysis of Ar I line shape characteristics

On the basis of five accurately recorded neutral argon (Ar i) line shapes (in the 4s-5p transition) we have recovered the basic plasma parameters i.e. electron temperature (T ) and electron density (N) using our new line deconvolution procedure in the case of three dierent plasmas created in a linear, low-pressure, pulsed arc discharge. The mentioned plasma parameters have also been measured using independent experimental diagnostic techniques. An excellent agreement has been found among the two sets of obtained parameters. This recommends our deconvolution procedure for plasma diagnostic purposes, especially in astrophysics where direct measurements of the main plasma parameters (T and N) are not possible. On the basis of the observed asymmetry of the Stark broadened line profile we have obtained not only its ion broadening parameter ( A) which is caused by the influence of the ion microfield on the line broadening mechanism but also the influence of the ion-dynamical e ect (D )o n the line shape. The separate electron (We )a nd ion (Wi) contributions to the total Stark width, which have not been measured so far, have also been obtained and represent the first experimental data in this field. We have found a stronger influence of the ion contribution to the Ari line profiles than the existing theoretical approximation provides. This is of importance for astrophysical plasma modeling and diagnostics.

Measured Stark widths of doubly and triply ionized silicon spectral lines

The Stark widths of ten Si III and seven Si IV spectral lines have been measured for the electron density range of 1.4*1023 m-3-3.0*1023 m-3 and for an electron temperature range of 29000-64000 K in a pulsed linear arc plasma discharge in O2 and SF6. Experimental values of Stark widths for ionized silicon spectral lines follow a simple dependence on the upper level ionization potential of the transition.

Stark widths of doubly ionized argon spectral lines

The Stark widths of 13 Ar III spectral lines have been measured at an electron density of and electron temperature of 38 000 K in a linear pulsed arc plasma discharge containing an argon - helium mixture. The measured values were compared to the existing calculated values based on semiclassical and semiempirical approximations.

Stark broadening and regularities of ionized bromine spectral lines

The authors report results of an experimental study of the Stark broadening of seven singly ionized, four doubly ionized and three triply ionized bromine spectral lines. The line profiles were recorded at the electron densities 1.1*1023 m-3 (Br II) and 8.5*1022 m-3 (Br III and Br IV) and temperatures of 3.6*104 K and 5.6*104 K respectively. The plasma was created in a linear pulsed discharge. Agreement within 20% with the theory of Dimitrijevic and Konjevic (1987) was found for the majority of Br II lines. Experimental values of Stark broadening parameters for neutral and ionized bromine spectral lines follow a simple dependence on the upper level ionization potential.