Particle acceleration is ubiquitous in the universe; however, our Sun provides a rare opportunity to observe energetic particles and their sources jointly. The acceleration mechanism in solar flares, tremendously enhancing (up to factors of ten thousand) abundances of rare elements like 3He and ultra-heavy nuclei (like 197Au and 207Pb), has been puzzling for more than 50 years. Flares associated with 3He-rich solar energetic particles have been commonly observed in jet-like forms indicating acceleration in magnetic reconnection on field lines open to interplanetary space. The goal of the team is to advance our understanding of the ion enhancement mechanisms by combining scientists with knowledge in different disciplines and research methods. The proposed team includes experimentalists with expertise regarding in-situ heliospheric and remote solar observations, as well as theoreticians and modelers of ion acceleration. The aims of the team are to 1) summarize the properties of 3He-rich solar sources, gathered with the recent high-resolution, extreme ultraviolet and photospheric magnetic field observations, 2) determine how these properties correlate with the in-situ energetic particle observations, and 3) conclude how these properties could constrain different models of particle fractionation and acceleration. It is a very timely topic, with the forthcoming launch of Parker Solar Probe scheduled for August 2018 and of Solar Orbiter scheduled for February 2020, carrying instrumentation for both solar in-situ and remote-sensing observations. The ISSI Team will be essential for promoting this area as a key focus of these missions with new discoveries being discussed during the Team meetings.