The operation of an FEL involves several steps: 1. Electron Acceleration: Electrons are accelerated to relativistic speeds using a particle accelerator such as a linear accelerator. 2. Undulator: The accelerated electrons pass through an undulator or wiggler, which consists of a series of alternating magnetic fields. 3. Emission of Radiation: As the electrons wiggle through the undulator, they emit radiation due to their acceleration. 4. Amplification: The emitted radiation is amplified as it travels along the undulator, resulting in a coherent and intense beam of light.
