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arXiv · 1404.3322

Abundance Enhancements in Impulsive Solar Energetic-Particle Events with Associated Coronal Mass Ejections

Donald V. Reames·Edward W. Cliver·Stephen W. Kahler
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Abstract

We study the abundances of the elements He through Pb in Fe-rich impulsive solar energetic-particle (SEP) events with measurable abundances of ions with atomic number Z>2 observed on the Wind spacecraft, and their relationship with coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). On average the element abundances in these events are similar to coronal abundances at low Z but, for heavier elements, enhancements rise as a power law in the mass-to-charge ratio A/Q of the ions (at coronal temperatures of 2.5-3 MK) to a factor of 3 at Ne, 9 at Fe, and 900 for 75 700 km/s), wider CMEs in our sample are related to SEPs with coronal abundances indicating hot coronal plasma with fully ionized He, C, N and O and moderate enhancements of heavier elements, relative to He, but slower (<700 km/s), narrower CMEs emerge from cooler plasma where higher SEP mass-to-charge ratios, A/Q, yield much greater abundance enhancements, even for C/He and O/He. Apparently, the open magnetic-reconnection region where the impulsive SEPs are accelerated also provides the energy to drive out CME plasma, accounting for a strong, probably universal, impulsive SEP-CME association.

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Donald V. Reames, Edward W. Cliver, Stephen W. Kahler. 2014-04-12. Abundance Enhancements in Impulsive Solar Energetic-Particle Events with Associated Coronal Mass Ejections. https://doi.org/10.1007/s11207-014-0547-1

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