PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE 107, Page 81-86, https://doi.org/10.69646/14sbac12p
PPROCEEDINGS OF THE XIV SERBIAN-BULGARIAN ASTRONOMICAL CONFERENCE, Vrnjačka Banja, Serbia, September 23-27, 2024, Eds. Milan S. Dimitrijević, Evgeni Semkov, Zoran Simić, Goran Damljanović, Momchil Dechev
Published by: Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia

A large number of galaxies have regular magnetic fields of several microgauss. Their evolution is described usnig the dynamo mechanism. It is based on helicity of the turbulent motions in the interstellar medium and differential rotation of the object. The process is described by mean field dynamo equation which is quite difficult to be solve both analytically and numerically. So different models taking into account geometrical shape of the object are used. One of the most popular approaches is connected with thin disc approximation which replaces the z-derivatives by algebraic expressions. However, as for discs with large half-thickness it does not give proper results. So we consider the thick disc model which can be useful for the objects with quite large half-thickness. Here we give the estimates of the magnetic field growth rate and check them numerically. It has been shown that for thick disc it is much more difficult to obtain the growing field. One of the most interesting questions (which has not been studied before) is connected with phase diagrams for the magnetic field. We have found a stable point and describe the typical phase trajectories leading to it