Energetic particle environment of Jupiter’s radiation belts

Jupiter possesses the strongest intrinsic magnetic field, the fastest rotation rate, the most volcanically active moon (Io), and the strongest radiation belts among all planets in the Solar System. Jupiter’s radiation belts are primarily composed of electrons, protons, and heavy ions (mainly oxygen and sulfur ions) moving at relativistic speeds. Both the particle flux and energy in these belts significantly exceed those of Earth’s radiation belts. As a natural particle accelerator, Jupiter’s radiation belts are not only of fundamental importance for understanding basic plasma physics processes, but also directly relevant to trajectory design, radiation protection for missions to the Jovian system, and the assessment of habitability of its moons. Under the combined influence of solar wind, planetary rotation, and natural satellites, Jupiter’s radiation belts exhibit highly complex spatial structures and dynamic evolution. However, due to a lack of observational data—especially in the core region of the radiation belts—current understanding remains substantially incomplete. Based on existing researches on Jupiter’s radiation belts, this article provides a systematic review of advances in the study of energetic particle environment of Jupiter’s radiation belts. It begins by introducing the spatial structure, energy spectrum characteristics, and pitch angle distribution of both electron and ion radiation belts, with comparisons made to the radiation belts of Earth and Saturn. The review further explores the origins, acceleration, and loss mechanisms of energetic particles in Jupiter’s radiation belts, and discusses the influence of natural satellites on the evolution of these particles. An overview is also provided of current empirical models based on observations and progress in numerical modeling based on physical processes. Finally, the paper concludes by analyzing key scientific questions that urgently need to be addressed in current research on Jupiter’s radiation belts and preliminarily outlines the challenges posed by Jupiter’s extreme radiation environment for future exploration missions to the Jovian system.