Energy Spectra and Composition of >30 keV/nucleon Ions at Interplanetary Shocks Observed at ACE and WIND
M. I. Desai, G. M. Mason, J. R. Dwyer
        University Maryland, College Park, Maryland, USA
J. E. Mazur
        Aerospace Corp, LA, California, USA
T. T. von Rosenvinge, D. Berdichevsky
        NASA/GSFC, Greenbelt, Maryland, USA
C. W. Smith
        Bartol Research Center, Delaware, USA

We analyze here the composition, energy spectra, and anisotropy of 30 keV/nucleon to 10 MeV/nucleon ions associated with 30 interplanetary shocks that were observed simultaneously at ACE and WIND during a two-year period starting from September 1997. In particular, we combine our measurements with those obtained by the solar wind plasma and the magnetic field experiments on board both spacecraft and compare our observations with the main predictions of various shock acceleration models such as the first-order Fermi process and the gradient-drift mechanism. We also investigate the spatial evolution of the shocks and its effect on the associated particle populations.