Dispersive Suprathermal Ion Events Observed by the Parker Solar Probe Mission

Abstract

During Encounter 11, Parker Solar Probe observed a low-energy dispersive ions event of solar origin. The event was observed in the SPAN-I and IS⊙IS EPI-Lo sensors. The event started at a few MeV energy in the EPI-Lo sensor and progressed down in energy to ≈1 keV and merged with the bulk of the solar wind. This event is substantially different from typical solar energetic particles because the energetic population shows a distinct peak in the energy spectrum that descends in energy (not a power-law tail). In this Letter, we explore this event’s nature, origin, and characteristics.