First order Fermi acceleration at multiple oblique shocks

Numerical results for particle acceleration at multiple oblique shocks are presented. We calculate the steady state spectral slope of test particles a ccelerated by the first order Fermi process. The results are compared to an alytical treatments for parameters where the diffusion approximation does a pply. Effects of injection and finite shock extent are included phenomenolo gically. We find the spectrum of accelerated particles to harden substantia lly at multiple oblique shocks and discuss the influence of the number of s hocks compared to the obliquity itself.