Supernova remnants are known to accelerate cosmic rays for their
non-thermal emission of radio waves, X-rays, and gamma-rays. Although
there are many models for the acceleration of cosmic rays in supernova
remnants, the escape of cosmic rays from this sources is yet
understudied.

We use our time-dependent acceleration code to study the acceleration of
cosmic rays and their escape from supernova remnants.

We carry out spherically symmetric 1-D simulations in which we simultaneously
solve the transport equations for cosmic rays, magnetic turbulence, and the
hydrodynamical flow of the thermal plasma.
The transport equations for cosmic-rays and magnetic turbulence are
coupled via the cosmic-ray gradient and the spatial diffusion
coefficient of the cosmic rays, while the cosmic-ray feedback onto the
shock structure is ignored. Our simulations span 100000 years, thus
covering the free-expansion, the Sedov-Taylor and the radiative phase of
the remnant evolution. During this time we keep all cosmic rays in the
simulation domain.

At later stages of the evolution cosmic-rays in a wide energy-band are
able to escape the remnant. We compare the results with common
analytic estimates for the escape-spectra.