Kicker magnets are dipole magnets used to rapidly switch a particle beam between two paths. Conceptually similar to a railroad switch in function, a kicker magnet must switch on very rapidly, then maintain a stable magnetic field for some minimum time. Switch-off time is also important, but less critical. Because a kicker magnet applies a particular lateral impulse to the beam, to achieve a fixed deflection angle, the strength of the kick must be accurately matched to the momentum of the particles. This is part of the power modulator's job.