Observability of Callisto's Inductive Signature During the JUpiter ICy Moons Explorer Mission

Abstract

Using hybrid simulations and analytical calculations, we investigate the observable magnetic perturbations during the 12 planned Callisto flybys of the JUpiter ICy moons Explorer mission. During four of these encounters, Callisto will be embedded within Jupiter's magnetospheric current sheet. In these cases, Callisto's Alfvén wings and ramside magnetic field pileup will partially obscure any magnetic signatures associated with induction in a conducting layer at the moon, thereby severely complicating attempts to further constrain properties of a possible subsurface ocean. During one of these flybys, the plasma interaction will even generate magnetic signatures that are qualitatively similar to an induced field from the moon's interior. In this case, highly accurate measurements of the upstream flow parameters and Callisto's ionosphere are required to disentangle the induction signal from plasma effects. For the remaining eight encounters, Callisto's plasma interaction is expected to be sufficiently weak for an unobstructed observation of the moon's inductive signature.