The Cassini spacecraft has spotted MeV (million electron volt) electrons coming from the shock wave around Saturn's magnetic field. These aren't the "ultra-high-energies" the story claims (those probably come from supernova shock fronts), but they are higher energy than the theory predicts.
This observation is of electrons accelerated where the magnetic field points more or less in the same direction as the shock front. (The case where the shock and the field are perpendicular is already known to accelerate electrons, and there are some models for how--but how well they describe Saturn's environment I don't know.) The shock front in question is from the solar wind hitting Saturn's magnetic field. For scale, the solar wind is mostly protons at about 1MeV kinetic energy and electrons with correspondingly smaller (1/2000) energy. This acceleration is able to bounce sling electrons back with energies as much as 2000 times what the incoming electrons have. (Usually smaller energies, though)
Together with the Fermi LAT spotting supernova remnant gamma rays we're starting to converge on some solid data we can use to test models with. Maybe we'll start to understand cosmic rays soon.