Authors: Anna Fitzmaurice (UMCP), James Drake (UMCP), Marc Swisdak (UMCP)

Extreme enhancements of helium-3 are commonly observed during impulsive SEP events, suggesting the presence of a preferential acceleration mechanism during solar energy release. While previous acceleration models have proposed that high-energy electron beams give rise to ion cyclotron waves which resonate with helium-3, there is minimal evidence that electrons will produce instabilities with enough energy in the correct frequency range to drive these enhancements. However, through linear stability analysis and fully kinetic plasma simulations, we have found that ion beams accelerated by magnetic reconnection produce two instabilities which can increase helium-3 temperatures by an order of magnitude: a parallel propagating, right-handed polarized mode and a strongly oblique mode, both unstable for a broad range of ion-scale frequencies. We propose that these waves propagate down from energy release sites and interact with heated material streaming up from the chromosphere. Due to its low abundance and unique resonant frequency, helium-3 will be heated to thermal speeds that exceed the Alfven speed, allowing for transport into the acceleration region. More abundant species, like helium-4, will remain sub-Alfvenic and will not be able to overcome the reconnection outflows, resulting in increased helium-3-to-helium-4 abundances in the acceleration region.