Coronal jet observed by Hinode as the source of a ^3He-rich solar energetic particle event

Abstract

We study the solar source of the ^3He-rich solar energetic particle (SEP) event observed on 2006 November 18. The SEP event showed a clear velocity dispersion at energies below 1 MeV nucleon^(−1), indicating its solar origin. We associate the SEP event with a coronal jet in an active region at heliographic longitude of W50°, as observed in soft X-rays. This jet was the only noticeable activity in full-disk X-ray images around the estimated release time of the ions. It was temporally correlated with a series of type III radio bursts detected in metric and longer wavelength ranges and was followed by a nonrelativistic electron event. The jet may be explained in terms of the model of an expanding loop reconnecting with a large-scale magnetic field, which is open to interplanetary space for the particles to be observed at 1 AU. The open field lines appear to be anchored at the boundary between the umbra and penumbra of the leading sunspot, where a brightening is observed in both soft and hard X-rays during the jet activity. Other flares in the same region possibly associated with 3He-rich SEP events were not accompanied by a jet, indicative of different origins of this type of SEP event.

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