  Cosmic-ray production in young supernova remnant (SNR) shocks is expected to
be efficient and strongly nonlinear. In nonlinear, diffusive shock
acceleration, compression ratios will be higher and the shocked temperature
lower than test-particle, Rankine-Hugoniot relations predict. Furthermore, the
heating of the gas to X-ray emitting temperatures is strongly coupled to the
acceleration of cosmic-ray electrons and ions, thus nonlinear processes which
modify the shock, influence the emission over the entire band from radio to
gamma-rays and may have a strong impact on X-ray line models. Here we apply an
algebraic model of nonlinear acceleration, combined with SNR evolution, to
model the radio and X-ray continuum of Kepler's SNR.
