Analysis of heavy ion SEP events detected by multiple spacecraft
Peter Zelina
University of Central Lancashire
Silvia Dalla, Mike Marsh
Solar energetic particles (SEPs) are accelerated and released into the heliosphere by solar flares and coronal mass ejections. The way in which SEPs are able to propagate across the magnetic field and reach a wide extent of locations in the heliosphere remains unclear. Launched in 2006, the two STEREO spacecraft offer a unique opportunity to study the perpendicular transport at similar radial and latitudinal locations but widely separated in longitude. We study large SEP events that produced significant increase in SEP iron intensity at multiple spacecraft between 2006 and 2014 using data from ACE, SOHO and STEREO. We study intensity time profiles and spectra, and the time variations of heavy ion ratios. We study SEPs of different energies, composition and charge states keeping into account the relative location between the source eruptive event and the spacecraft. We focus on transport effects and differences in propagation of heavy ions. We discuss which effects may be responsible for the propagation of SEPs to longitudes on the far side of the Sun with respect to their parent active region.