---
author:
- 'M. Prouza and R. Šmída'
date: 'Received ??? ??, 2002, accepted ??? ??, 2003'
title: 'The Galactic magnetic field and propagation of ultra-high energy cosmic rays'
---

Introduction
============

The origin of the high-energy cosmic rays and the ultra-high energy cosmic rays (UHECRs[^1]) is one of the major unresolved questions in astrophysics, with a degree of uncertainty increasing with energy of the particles. The situation is more complicated than in radio, optical or TeV gamma-ray astronomy, where we observe arrival directions of non-charged photons and we can easily locate the positions of their sources from these observations. However, because it is generally accepted that the primary particles with energies above $10^{12}$ eV or significant part of them are fully ionized and therefore charged atomic nuclei, we must consider the influence of magnetic fields on their propagation from the source to the Earth. This deflection prevents unambiguous identification of possible sources.

It is generally believed that the bulk of CRs with the energy below the knee (around $3\times10^{15}$ eV) has Galactic origin and its main production mechanism is an acceleration by supernovae shocks ([@axford]). But the origin of the knee remains a mystery. CRs with energies above the 