Mixed particle acceleration at CME‐driven shocks and flares

A recent study of Cane et al. 2003 showed that in some intense SEP events, the time‐intensity profiles exhibit two peaks, with an earlier one having a high Fe / O and a later one with a low Fe / O ratio. They suggested that these two‐component events are due to CMEs and their accompanying flares occurring together, with the first peak being flare‐related and the second peak being CME‐driven shock related. In this paper, we develop a model which examines particle acceleration and transport when both flares and CME‐driven shocks are present. We study time‐intensity profiles for three different scenarios: a pure shock case, a pure flare case and a shock‐flare‐mixed case. Using reasonable estimates of the relative timing between CMEs and associated flares, we find that a large portion of the flare accelerated material is subject to absorption and re‐acceleration by the CME‐driven shock. Consequently, the time intensity profile for the shock‐flare‐mixed case shows an initial rapid increase, owing to particles accelerated at the flare and followed by a plateau similar to that of a pure shock case.