High-energy, ultrafast-moving particles have a wide array of both applied and fundamental scientific uses, such as imaging biological tissue in detail and probing questions about the building blocks of matter. But accelerating particles to high energies is not a cheap or easy task. The advanced accelerators being used for that purpose rely on multikilometer-scale facilities. That’s because RF cavities—metal chambers that generate the electric fields used to accelerate particles—have fundamental limits that max out their electric field gradients at tens of megaelectron volts per meter. At those gradients, it takes kilometers to get particles up to the tens of gigaelectron-volt energies achieved at facilities such as SLAC and the German Electron Synchrotron (DESY). But there’s another approach that can produce electric field gradients that are thousands of times as strong as those produced in RF cavities.
When a laser pulse is sent through an ionized plasma—a sea of electrons and...
