A preliminary analysis of 3He-rich solar energetic particle events measured via ISOIS during Parker Solar Probe’s orbit 19

Authors: G.D. Muro (Caltech), C.M.S. Cohen (Caltech), E.R. Christian (NASA/GSFC), A.C. Cummings (Caltech), A.W. Labrador (Caltech), R.A. Leske (Caltech), D.J. McComas (Princeton), N.A. Schwadron (Princeton/UNH) , M.E. Wiedenbeck (NASA/JPL), Z. Xu (Caltech)

A series of 3He-rich solar energetic particle (SEP) events was observed by Parker Solar Probe (PSP) from 30 March 2024 to 7 April 2024 at radial distances between 0.09 to 0.33 AU. Several active regions were well connected to PSP, as well as Solar Orbiter and STEREO A, throughout this period and this study attempts to distinguish the likely SEP source based on low coronal activity. Features in the time-intensity profiles of these SEP events were consistent with 3He-rich events over a wide longitudinal range as PSP traveled over 140° with respect to Earth until it nearly aligned with Solar Orbiter towards the observational period. This study uses ∼1-20 MeV/nucleon data from in-situ instruments to measure ion ratios and estimate injection times via velocity dispersion analysis. To characterize the solar activities holistically, we also utilize remote sensing methods to understand how Type III radio bursts, X-ray measurements, EUV images and coronagraphs relate to these widespread 3He-rich SEP events.