Distribution of solar energetic particles in 3-dimensional coronal and interplanetary magnetic fields

Abstract:

Solar energetic particles (SEPs) are produced either in solar flares or by coronal mass ejection (CME) shocks. While a strong CME shock can be large enough to cover a significant fraction of the solar surface, a typical solar flare must be very narrow. Many SEP events with the impulsive flare signature of an enhanced He3/He4 ratio can be seen simultaneously by several spacecraft located over a wide range of longitudes and latitudes. Also, as indicated by EUV waves appearing on the solar surface, CME shock waves expand at a finite speed in the corona. All these suggest that SEP source is not uniformly injected and distributed on the sun. However, SEP often can reach a nearly uniform distribution known as SEP reservoir throughout the inner heliosphere within less than a few days. To understand these, we use our 3-d model of SEP coronal and interplanetary propagation including perpendicular diffusion to investigate the behavior of SEP intensity and anisotropy seen at 1 AU. We examine how various possible scenarios of magnetic connections to a CME or flare site and particle injection profiles on the sun might affect the results.