Centrum Astronomii
Wydział Fizyki, Astronomii i Informatyki Stosowanej, Uniwersytet Mikołaja Kopernika

Dynamo coefficients in Parker unstable disks with cosmic rays

Otmianowska-Mazur K., Kowal G., Hanasz M.

We investigate a three-dimensional (3D) numerical model of the Parker instability with cosmic rays and shear in a galactic disk and compute the components of the dynamo coefficients \hat{α} and \hatβ from the electromotive force (EMF) obtained directly from our simulations. In our model we apply well-known statistical procedures in order to fit the modeled EMF in terms of the dynamo tensors. Nevertheless, we do not solve all problems with the physical interpretation of the dynamo tensors prescribed in the way of Rädler (\cite{raedler80}). We find that the presented methods give us the possibility to compute the coefficients with a desired statistical quality. The obtained values of αxx (along the radial direction in a galaxy) are of order of a few km/s, while the values of αyy (along the azimuthal direction) are one order of magnitude smaller.

Słowa kluczowe
Galaxies: Ism, Galaxies: Magnetic Fields, Methods: Numerical, Magnetohydrodynamics