The maximum momentum of particles accelerated at cosmic ray modified   shocks
  Particle acceleration at non-relativistic shocks can be very efficient, leading to the appearance of non-linear effects due to the dynamical reaction of the accelerated particles on the shock structure and to the non-linear amplification of the magnetic field in the shock vicinity. The value of the maximum momentum $p_{max}$ in these circumstances cannot be estimated using the classical results obtained within the framework of test particle approaches. We provide here the first attempt at estimating $p_{max}$ in the cosmic ray modified regime, taking into account the non-linear effects mentioned above. 
Pasquale Blasi (1), Elena Amato (1), Damiano Caprioli (2) ((1)   INAF/Arcetri Astrophysical Observatory, (2) Scuola Normale ...