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Magnetic fields with random initial conditions in discs with Kepler rotation curve
Magnetic fields of various astrophysical objects
are described using the dynamo mechanism. Corresponding
equations in the three-dimensional case are quite difficult
to be solved. So, the two-dimensional models can be useful
for such problems. For galactic and accretion discs, it is
convenient to use the no-z approximation. The initial conditions
for the magnetic field have a special interest. It
seems that the seed field is generated by the Biermann
mechanism, and after that they are transformed by the
small-scale dynamo which gives a random structure of
the field. Previously it has been shown that random initial
conditions can lead to generation of large-scale magnetic
field structures which correspond to the galaxies at the
moment. In this work, we have studied generation of the
magnetic field for the case of Kepler rotation curve, which is
mostly suitable to the accretion discs. Here, we have studied
the field generation in the thin disc for rapidly changing
angular velocity in the case of simple model assumptions.