cyclotron resonance

Cyclotron resonance occurs when a charged particle orbiting in a magnetic field absorbs electromagnetic energy because the electromagnetic and orbital frequencies match. This phenomenon is fundamental to the operation of cyclotrons, a type of particle accelerator.12

In a classical cyclotron, an accelerating electric field oscillates at a fixed frequency, synchronized with the orbital frequency of particles in a uniform magnetic field. As particles cross the gap between electrodes called "dees," they are accelerated. This process creates a spiral path of increasing radius. The energy a particle gains is limited by relativistic effects that cause its mass to increase, leading to a decrease in orbital frequency and a loss of synchronization with the accelerating voltage.2