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Understanding the Composition of Solar Energetic Particle Events


May 23, 2014, 3:30 p.m. - 5 p.m.
Geology 6704

Presented By:
Christina Cohen
Caltech

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By the 1990’s sense had finally been made of the variable composition observed in solar energetic particle (SEP) events. The importance of solar flares was modified by the observation of coronal mass ejections (CMEs) and their ability to drive interplanetary shocks. The ‘two-class’ paradigm was established allowing the characteristics of an SEP event to be directly related to the acceleration mechanism at work. This neat picture was disrupted by the first observations from the Solar Isotope Spectrometer on the Advance Composition Explorer, launched in August 1997. Although the two acceleration mechanisms remain a distinguishing aspect of SEP events, additional puzzles have arisen in explaining the observed composition in some events. With the launch of the twin Solar Terrestrial Relations Observatory spacecraft in October 2006, the capability of routinely observing an SEP event from multiple vantage points was obtained. This talk will present the evolution in our understanding of SEP event composition, including how this new tool has contributed.