We describe a test particle simulation designed to study energetic charged particle acceleration at oblique fast-mode shocks when magnetic fluctuations exist upstream and downstream of the shock. The technique consists of integrating along exact particle orbits in a system where the angle &thgr;1 between the shock normal and mean upstream magnetic field, the level of magnetic fluctuations, and the energy of injected particles can assume a range of values. This allows us to study time-dependent shock acceleration under conditions not amenable to analytical techniques. To illustrate the capability of the numerical mode, we consider proton acceleration under conditions appropriate for interplanetary shocks near 1 AU, including large-amplitude transverse magentic fluctuations derived from power spectra of both ambient and shock associated MHD waves.

With all other parameters held fixed, protons injected at &thgr;1=0¿ and &thgr;1=60¿ shocks are accelerated from 10 keV to ~100 keV and ~1 MeV, repectively, within 300 gyroperiods by a combination of the shock drift and first-order Fermi processes. The energy spectrum downstream of the 60¿ shock can be fit with two power laws, with spectral exponent &ggr;=1.7 from 10 keV to ~80 keV and &ggr;=2.6 from ~ 80 keV to 800 keV. Results are also presented for the situation where the variance and upstream extent of the shock-associated waves at the 60¿ shock are reduced relative to the values used at the 0¿ shock.