Authors: Nariaki Nitta (LMSAL), Meng Jin (SETI/LMSAL), Christina Cohen (Caltech)

In the commonly used classification scheme of solar energetic particle (SEP) events, particles in gradual SEP events are thought to be accelerated at shock waves driven by coronal mass ejections (CMEs) and to have the composition similar to that of the solar wind. However, some gradual SEP events show enhancement of heavy ions such as Fe. One of the competing scenarios for Fe-rich gradual SEP events invokes quasi-perpendicular shocks, which may preferentially accelerate suprathermal particles that already have flare-like composition, enriched in heavy ions. We attempt to test this hypothesis. Using advanced numerical simulations, we compute the parameters of CME-driven shock waves, including the shock angle, namely the angle of the magnetic field lines in the upstream with the shock normal. We model eight eruptions that produced SEPs as observed at more than one of three locations around 1 AU, namely, near Earth and STEREO-A and -B. We do not find a strong correlation between Fe-rich SEP events and large shock angles. We discuss the results including alternative scenarios for the variations of the SEP composition and the uncertainties in the simulation results.