Particle Acceleration at Coronal Mass Ejection Driven Shocks
G.P. Zank, W.K.M. Rice, and J. Lu
Bartol Research Institute, The University of Delaware, Newark, DE 19716

There is increasing evidence to suggest that energetic particles observed in "gradual" solar energetic particle (SEP) events are accelerated at shock waves driven out of the corona by coronal mass ejections (CMEs). Energetic particle abundances suggest too that SEPs are accelerated from in situ solar wind plasma rather than from high temperature flare material. Virtually no models exist which describe the injection, acceleration and escape of ions accelerated dynamically at the propagating interplanetary shock. We present here a dynamical time-dependent model of particle acceleration at a propagating evolving interplanetary shock which includes the determination of the particle injection energy (injection here refers to the injection of particles into the diffusive shock acceleration mechanism), the maximum energy of particles accelerated at the shock, energetic particle spectra at all spatial and temporal locations, and the dynamical distribution of particles that escape upstream and downstream from the evolving shock complex. As the shock evolves, energetic particles are trapped downstream of the shock and diffuse slowly away. In the immediate vicinity of the shock, broken power law spectra are predicted for the energetic particle distribution function and the evolution of the spectrum in time will be described. Intensity profiles for particles of different energies are computed and the relation between arrival times, maximum predicted energies, and shock propagation characteristics are described. These results are of particular importance in the context of predictive space weather studies.