What Observations Would an Energetic Neutral Atom Imager Have Made During the Voyager 2 Flyby of Uranus?

Abstract We present large‐scale simulations of energetic neutral atom (ENA) emissions at Uranus from a spacecraft viewpoint. Models of magnetic field, extended hydrogen exosphere, moon‐sourced neutral tori, and proton radiation belt are implemented into a simulator to evaluate the production of ENAs for = 1–15. Our ENA maps are first computed with a resolution of 0.25 × 0.25 degrees to cover a field of view of 90 × 120 degrees, before undergoing post‐processing to account for the resolution and response of a typical ENA imager. Our key data products consist of spatiotemporal distribution movies along the Voyager 2 trajectory within ∼52 from Uranus. Our simulator considers the possibility that the proton belt does not populate the region 4.1, peaks at = 3 or = 1.5. Our results suggest a strong probability of detecting ENAs resulting from charge exchange between the proton belt and the exosphere with a Cassini‐like ENA imager. The exosphere‐sourced ENA production rate for our worst‐case scenario, in which no protons populate the inner region ( 4.1), remains comparable to those typically measured at Saturn by the Cassini ENA detector during quiet magnetospheric activities in 2004–2017. Although the detectability of ENAs from icy moons environment cannot be confirmed due to significant uncertainty regarding neutral density levels, our results reveal that an ENA imager would have provided at least key constraints on the distribution and intensity of Uranus's proton belt and a first glance at its dynamical behavior during a compressed phase of Uranus's magnetosphere.