bunch compression

Bunch compression is a technique used in particle accelerators to decrease the length of a group of particles (called a "bunch") while increasing their energy spread temporarily. By applying specific electromagnetic fields, the particles at the front and back of the bunch are sped up or slowed down, causing the bunch to "compress" in space. This process results in a shorter, more densely packed bunch, which is essential for improving the performance of experiments, such as increasing the intensity of collisions or enhancing the quality of the generated X-ray or electron beams.