Planets like Earth, Jupiter and Saturn, with global magnetic fields of their own, are surrounded by so-called radiation belts: Trapped in the magnetic field, fast moving charged particles such as electrons, protons, and heavier ions whiz aroun, thus forming the invisible, torus-shaped radiation belts. With their high velocities reaching almost the speed of light, the particles can ionize other molecules when they collide, creating a hazardous environment that can also be dangerous to space probes and their instruments. In this respect, the gas giant Jupiter sports the most extreme radiation belts in the solar system. In their new publication, researchers from the MPS, the California Institute of Technology (U.S.), the Johns Hopkins Applied Physics Laboratory (U.S.), the Laboratory of Instrumentation and Experimental Particle Physics (Portugal), and the Academy of Athens (Greece) now present the most comprehensive study to date of the heavy ions in Jupiter's inner radiation belts.