Pulsars are the most powerful magnets in the universe. A new simulation -- a “pulsar in a box” -- is giving scientists insights into the extreme physics of these spinning neutron stars. The simulation shows that most of the electrons (blue, with lighter shades representing higher energies) tend to race outward from the magnetic poles. But some medium-energy electrons scatter wildly, even heading back to the pulsar. The positrons (red) mostly flow out at lower latitudes, forming a relatively thin