project 176002 "Influence of collisions on astrophysical plasma spectra"
supported by the Ministry of Education, Science and Technological Development of Serbia

This project is the continuation of long standing research on the influence of atomic collisional processes on the spectra of astrophysical and laboratory plasmas. Investigations were performed within the following topics:
1. Determination of parameters of Stark broadening and investigations of its influence on spectral lines of white dwarfs and of chemically peculiar A and B type stars. This research field is particularly actualized with the development of satellite born astronomy, so that spectral lines of trace elements are becoming more and more astrophysical significant. For determination of Stark broadening parameters we used semiclassical perturbation and modified semiempirical method, and results were compared with observed stellar spectra and synthetic ones, modeled with SYNTH2 and PHOENIX code. Our results were entered in FP7 project VAMDC 239108 and international base data STARK-B and Serbian Virtual Observatory. Except for Astrophysics, obtained results are importance and for research of laboratory plasma, plasma technologies, etc.
2. We studied experimentally influence of solar activity on the characteristics of waveguide Earth-ionsphere, as well as the influence of electrical discharges in the Earth`s atmosphere by permanent measuring of the amplitude and phase of VLF radio-wave. Measuring of the amplitude and phase of narrowband transmitters within the range 10-30 kHz by using AbsPAL and AWESOME systems. We analized daily changes in the ionsphere which are caused by reinforced radiation from the Sun during flares and the electron density during the flares as well as in the period when regular conditions in the D layer of ionosphere are established. We continued work within the frame of European action COST ES0803.
3. We studied the influence of inelastic atom-Rydberg atom and radiative ioa-atom collision processes on the kinetics of weakly ionized plasma of Sun, white dwarfs and Earth`s ionosphere. As the results, the needed rate coefficients of the chemi-ionization/recombination and excitation/deexitation processes in atom Rydberg atom collisions, as well as coefficients of the absorption caused by ion-atom colissions in UV and VUV spectral regions will be determined.
4. Project task “Solar wind” opened investigations of the interactions of beams with highly energetic electrons, formed in varios violent events on the Sun with interplanetary plasma. We investigated relationship between Langmuir oscillations/waves and the type III solar radio bursts.

project 451-03-39/2016/09/15 "Improving the accuracy of spectroscopic diagnostic models for astrophysical and magnetic fusion plasmas"
supported by the Ministry of Education, Science and Technological Development of Serbia
The program of integrated activities "Pavle Savić"

Astrophysicists share with laboratory plasma physicists an interest for the details of atomic line shapes emitted in plasmas. Many studies have demonstrated that an exhaustive analysis of spectral line shapes provides invaluable information on the emitter environment. Ongoing progresses in observations drive a parallel effort in the modeling, since there can be no accurate diagnostic without a deep understanding of the interactions between the atomic emitters and the plasma surrounding them. The aim of this project is to improve the accuracy of the spectroscopic models involved in astrophysics for the diagnostic of stellar atmospheres. The project will join the expertise of French physicists involved in the diagnostic of magnetic fusion and astrophysical plasmas (J. Rosato, R. Stamm, I. Hannachi, M. Meireni, Aix-Marseille University; S. Sahal-Bréchot, Paris-Meudon Observatory) with Serbian astrophysicists (Z. Simić, M. S. Dimitrijević, Astronomical Observatory;
A. Kovačević, Faculty of Mathematics; D. Tankosić, N. Martinović, IHIS – Technoexperts Belgrade; A. Valjarević, Faculty of Sciences Kosovska Mitrovica) determined to obtain accurate information from observed line shapes. A link to magnetic fusion will be established through applications of the line shape models to the diagnostic of divertor plasmas. Applications to industrial plasmas such as in light sources, laser welding and piercing of metals will also be performed. In magnetic fusion, the international project ITER (under construction in France; www.iter.org) will be diagnosed by hundreds of spectroscopic lines of sight observing the continua and numerous spectral lines emitted in the edge and main plasmas (e.g. “Progress in the ITER Physics basis”).