the extragalactic sources. The last mentioned method is probably also the most reliable for the large scale structure. This method is also used for the determination of the global structure of the magnetic fields in the external galaxies. From these measurements it follows that the Galactic magnetic field has two components — regular and turbulent ([@rand]).

Random fields appear to have a length scale $50 \div 150$ pc and they are about two or three times stronger than the regular field. These random field cells have such a small scale (in comparison with kiloparsec scale of Larmor radii of UHECRs) that they are not modelled within global GMF models. However, it follows from recent work of [@harari] or [@jaime] that turbulent field really plays key role in the clustering, magnification or multiplying of the source images. Therefore we introduced random fields into our simulations, respecting the fact that such fields are very strong especially in Galactic arms regions.

We are able to summarize our direct experimental knowledge about the Galactic magnetic field in several statements (according to [@beck], [@widrow] and [@han_new]):

-   [The strength of the [*total*]{} magnetic field in the Galaxy is $(6 \pm 2)$ $\mu$G in the disk 