The temporal and spatial development of MeV proton acceleration at interplanetary shocks

Particle events observed in association with interplanetary shocks exhibit a wide variety of different features. In this paper we will demonstrate how these features can be understood in terms of a spatially and temporally varying shock efficiency and the subsequent interplanetary propagation. The examples presented here will show that while the location of the observer relative to the shock is an important factor in determining the event properties, the radial and temporal evolution of the shock also plays an important role. In particular, there are shocks which in a given energy range predominately accelerate particles close to the Sun, while in others the shock efficiency increases as they propagate outward. Another goal of this paper is to demonstrate that the black box model used here is able to fit the data.