Multi-spacecraft observations during a series of three solar energetic particle events in May, 2009

Abstract

At the end of the prolonged solar minimum of solar cycle 23 a fleet of well-separated spacecraft were monitoring to observe solar energetic particle (SEP) events. In the beginning of May 2009 a series of three SEP events on the first, second and fifth of May were observed by ACE and WIND. Except from the first event, energetic electrons and protons were also detected by STEREO A. The source region of the first two events is clearly identified with the help of SOHO/EIT and STEREO/EUVI to be at the west limb for the Earth. STEREO B EUVI observations together with multipoint radio measurements support an eastern source for the third event. However in-situ particle time-intensity profiles and anisotropies suggest a well-connected source, rather than the eastern AR separated by 100 degrees from the footpoint of STEREO A. Combining 3D propagation simulations with multi-point observations, we discuss the propagation conditions for this series of SEP events.

Publication
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011