Head: Dr. P. Duchlev
Nonstationary processes in the solar atmosphere leading to generation of active phenomena are studied. The sector takes part in the Joint Organisation for Solar Observations (JOSO) and in the SOHO programmes for coordinated ground-based and orbital observations of the Sun.
Solar physics in Bulgaria is a young field of Bulgarian science. In 1958 Department of Astronomy became an independent division of the Bulgarian Academy of Sciences (BAS).
In this new section A. Bonov, M. Kalinkov, D. Raikova and their colleagues worked on the Sun’s problems and the solar activity. In 1977 Vladimir Dermendjiev took up his duties as a research worker at the Department of Astronomy in BAS. In 1985 he founded a division “Sun” in the Department of Astronomy, now Institute of Astronomy. He laid the foundations of systematic and detailed researches of the Solar physics in our country. Furthermore, V. Dermendjiev was associated lecturer of the solar physics at the Astronomy Department in the faculty of Physics at Sofia University.
There are three main directions of solar research in “Sun” division at the Institute of Astronomy: 1) Processing of observational materials from the observatories in other countries using the Joyce Loebl microdensitometer in National Astronomical Observatory-Rozhen;
2) Magneto-hydro-dynamic (MHD) rendering, modeling and computer simulation of the solar activity phenomena;
3) White-light solar observations.
The processing of observational materials is a part of the energetic mutual collaborations between “Sun” division and: the Meudon Observatory in Paris and the Institute d’Astrophysique Spatiale in Orse, France; the Astronomical Observatory of Wroclaw University in Poland; the Astronomical Observatory in Ondřejov, Czech Republic; the Astronomical Institute in Tatranska Lomnica, Slovakia; the Astronomical Institute in Bucharest, Romania; the IZMIRAN in Troitsk, Russia; the Astronomical Observatory of Istanbul University in Turkey. One of the main tendencies of Dermenjiev’s scientific researches was the MHD modeling of different activity phenomena. His researches in this direction laid the beginnings of the solar MHD and plasma physics in our country. In 1992-1993 a solar station in the Rozhen National Astronomical Observatory in the Rodopi Mountains was built. It is situated on the altitude of 1750 m. This is a tower with 8-meter dome where a 15-centimeter photosphere telescope with H filter and spectrograph has been assembled. White-light solar observations carry out everyday in the people observatories in Smolian, Dimitrovgrad and Kardjali.