halo is extremely important for the cosmic-ray trajectories, but it is very poorly known, as we stated above. Obvious approach to this problem is represented by the work of [@stanev1], where the field above and under the Galactic plane is taken as exponentially decreasing: $$|B(r, \Theta, z)| = |B(r, \Theta)| e^{(-|z|/z_0)},$$ where $|B(r, \Theta)|$ is the vector sum of magnitudes of $B_r$ and $B_{\Theta}$ with the $z_0$ = 1 kpc[^4].

We used this described model of GMF as the basis for our simulations. Strictly speaking, we simply add toroidal and poloidal field components to this model, as it is detailed in the next subsection.

Alternative models with another field configurations were also proposed. The another possible but according to recent observations a bit less probable configuration is the so-called ASS-S configuration, axisymmetric configuration without reversals and with even parity ([@stanev1]). However, this configuration has one advantage. It could be much easier modeled using of the very popular dynamo model of magnetic field generation ([@elstner]). The bisymmetric mode can also be obtained from dynamo model, but in such case the use of strong non-axisymmetric perturbations is necessary. The other two possibilities of magnetic field configurations — bisymmetric dipole type (BSS-S) and 