In 2019, it received an upgraded “beam dump,” which is like the runaway truck ramp for the high-powered beams inside the SPS. When things have energy and make waves, those waves can interact with each other and create weird little loci where energy is amplified. “In accelerator physics, an understanding of resonances and nonlinear dynamics is crucial for avoiding the loss of beam particles,” the scientists explain in the paper. And harmonics in complex systems affect any experiment where particles interact inside a vessel—like nuclear fusion research in tokamaks. Inside the SPS, particles only have two degrees of freedom, which doesn't sound so complex.