Escaping the accelerator; how, when and in what numbers do cosmic rays
  get out of supernova remnants?
  The escape of charged particles accelerated by diffusive shock acceleration
from supernova remnants is shown to be a more complex process than normally
appreciated. Using a box model it is shown that the high-energy end of the
spectrum can exhibit spectral breaks even with no formal escape as a result of
geometrical dilution and changing time-scales. It is pointed out that the bulk
of the cosmic ray particles at lower energies must be produced and released in
the late stages of the remnant's evolution whereas the high energy particles
are produced early on; this may explain recent observations of slight
compositional variations with energy. Escape resulting from ion-neutral
friction in dense and partially ionized media is discussed briefly and some
comments made on the use of so-called "free escape boundary conditions".
Finally estimates are made of the total production spectrum integrated over the
life of the remnant.
