The propagation of nonlinear ion-acoustic waves (IAWs) in a magnetoplasma having superthermal inertialess electrons and inertial warm adiabatic ions is examined. In this regard, Zakharov Kuznetsov (ZK) equation is derived in order to investigate the characteristics of the ion-acoustic solitons (IASs) in the small but finite amplitude limit. Using the Hirota bilinear method, both single and two-solitons solutions of the two and three-dimensional ZK equations are obtained. According to the parameters of Van Allen radiation belts, the effects of superthermality, magnetic field, ion number density, and the ion temperature on the profile of both single and two-solitons are explored. The estimates of the spatial extent of the interaction of solitons in the outer radiation belts are also given.