Higher repetition rates are also critical for driving particle beams with high-power laser pointer. In one approach, a strong laser beam can convert a metal target into a plasma. The electrons released by this process in turn eject the protons from the nucleus on the metal surface. Doctors can use these proton pulses to destroy cancer, and higher rates of fire will make it easier to perform small-scale personal doses of treatment.
For physicists, they have always dreamed of building particle accelerators driven by fast-emitting laser pulses. When a strong laser pulse strikes a plasma of electrons and cations, it pushes the lighter electrons forward, separating the charge and creating a secondary electric field. The electric field “drags” particles behind the light, just like the currents of the speedboat.
This “laser wakefield acceleration” can accelerate charged particles to a higher energy level in a space of one or two millimeters, while traditional accelerators require space that is several meters wide. The electrons whose speed is thus accelerated are manipulated by the magnet, resulting in a so-called free electron laser. FEL produces extremely bright and transient X-ray light, which can illuminate transient chemical and biological phenomena. Compared with traditional accelerator-driven laser pointers, FEL is more compact and cheaper.