The cyclotron frequency or gyrofrequency is the frequency of a charged particle moving perpendicular to the direction of a uniform magnetic field B (constant magnitude and direction). Since that motion is always circular, the cyclotron frequency is given by equality of centripetal force and magnetic Lorentz force
with the particle mass m, its charge q, velocity v, and the circular path radius r, also called gyroradius.
The angular speed of the rotation is then:
Giving the rotational frequency (being the cyclotron frequency) as:
It is notable that the cyclotron frequency is independent of the radius and velocity and therefore independent of the particle's kinetic energy; all particles with the same charge-to-mass ratio rotate around magnetic field lines with the same frequency.