The theoretical researches are devoted by the following problems:
• The effects of magnetic energy increasing in a region of a quite strong magnetic field have been researched by means of 2D-hydromagnetic computer simulation for increasing of the magnetic energy in a homogeneous plasma medium (Dermendjiev and Buyukliev, 1987).
• The nature of elementary eruptive phenomena has been researched (Dermenjiev 1984).
Part of Dermenjiev’s theoretical researches has been devoted to the physical mechanisms that bring up to the appearance and development of surge prominences (Dermendjiev, Buyukliev and Stavrev 1989).
• The MHD rendering of the prominence plasma weak leaking into the solar corona has been suggested (Rusin, Dermendjiev, Rybansky, Buyukliev, 1990).
By researches of the faint coronal H-alpha emission, observed in the near vicinity of the prominences, a physical process of the instability in the coronal plasma has been examined. In this process the participation of the local magnetic field traced by prominence is of great importance (Dermendjiev et al., 1994, Dermendjiev, Mouradian and Leroy, 1994).