Authors: Bishwas L. Shrestha (Princeton University)

Pickup ions (PUIS) produced by the ionization of interstellar and inner-source neutral atoms and subsequently advected by the solar wind are a critical yet poorly understood component of the heliosphere’s particle population. Near 1 au, PUIs exhibit distinctive velocity distribution functions extending to roughly twice the solar wind speed, making them an essential seed population for acceleration to suprathermal energies.

NASA’s IMAP mission is designed to address the long-standing “injection problem” by providing high-resolution, species-resolved measurements of PUIs and suprathermal ions through its SWAPI and CoDICE instruments. By combining IMAP data with complementary PUI observations from other missions, such as MMS and STEREO/PLASTIC near 1 au and New Horizons/SWAP in the outer heliosphere, we can assemble a multi-mission dataset that advances our understanding of PUI energization across a broad range of heliocentric distances. This presentation focuses on the combined science objectives enabled by these multi-spacecraft PUI observations, with particular emphasis on identifying and advancing our understanding of particle injection and energization in the heliosphere.