The Byurakan Astrophysical Observatory after V.Ambartsumyan of NAS RA is conducting research on formation of magnetic fields from zero in our Galaxy and other galaxies. The work is supervised by Ruben Andreasyan, the Head of the "Active Galaxies" Scientific Research Department of the Byurakan Observatory, Candidate of Physical and Mathematical Sciences.
"Dynamo mechanisms" have so far been used to study the amplification of already existing weak magnetic fields during the galaxy life and configurations that can be formed in different galaxies, depending on the amount of extremely low-density plasma in them and the movement of that plasma. Moreover, the mechanisms for the formation of initially weak magnetic fields are either kept silent or it is said that these fields were formed at the early stages of the formation of the universe.
Our work attempts to explain the formation of magnetic fields through the presence of active processes taking place in galaxies. That is, a strong outflow of ionized matter from the central regions of galaxies or an inflow of matter (accretion) on those regions. In case of general rotation of galaxies and the presence of the mentioned conditions, the Birman mechanism ("battery effect") works, which is able to generate magnetic fields from zero. The essence of the mechanism is that the masses of electrons and protons in the outflowing or inflowing plasma differ by more than 3 orders of magnitude, and therefore their interaction with the particles of the rotating gaseous medium in galaxies is very different. As a result, the rotational component of the velocity of electrons differs from the rotational component of the velocity of protons at any point in the galaxy, while maintaining the state of electro neutrality. It leads to formation of circular electric currents, as a result of which dipole magnetic fields are formed, which can later be amplified or altered by already known dynamo mechanisms.
A study has been conducted for our Galaxy, taking into account some peculiarities obtained from observations on interstellar gas dynamics. Using planar approximations, when the thickness of the gas layer is much smaller than its radial sizes, modeling of the inversion of the galaxy's magnetic field (reversal of the field direction) was performed. It has been shown that it is theoretically possible to generate such magnetic fields in which while moving away from the center of the galaxy both one-time and two-time changes in the direction of a circular magnetic field can be observed. Using the data of pulsars with high value of Faraday rotation it has been shown that in the plane of the Galaxy the direction of the magnetic field in the circle bounded with 5 and 7 kpc from the center of the Galaxy is opposite to the magnetic field of the other part of the Galactic plane. This result is in good agreement with the above models complied with the theoretical research. The work is of fundamental importance, as an attempt is made to explain the formation of magnetic fields in galaxies from zero by a new, and, in our opinion, the most effective Birman mechanism,” said Ruben Andreasyan.
The research was carried out within the framework of the project "Study of Magnetic Fields of Galaxies". The results of the work were published in the "Астрономический журнал" of the Russian Federation.
The co-authors of the work are young scientists: Yevgeny Mikhailov, an Associate Professor of the Faculty of Physics of Moscow State University after M.Lomonosov, and Hasmik Andreasyan, Candidate of Physical and Mathematical Sciences.