Acceleration in the Low Corona of CMEs Associated with Solar Energetic Particle Events

We report here on the initial accelerations of coronal mass ejections (CMEs) associated with 25 MeV solar energetic proton events (SEPs) during the period 1980-2017. Primary CME observations in the low corona were obtained at Mauna Loa Solar Observatory (MLSO) and, where possible, they were combined with spacebased observations from the SMM C/P, P78-1 Solwind, and SOHO LASCO coronagraphs. We identified >100 SEPs with associated MLSO observations of CMEs, and we were able to combine many of those with the spacebased coronagraphs to reveal the initial and middle-coronal acceleration of the SEP-associated CMEs. We were able to determine both an instantaneous maximum acceleration as well as an average acceleration in the low corona. We compare these measured values with proxy determinations of acceleration and with their use in predicting SEP properties.