# gyrofrequency

The gyrofrequency, also known as the **cyclotron frequency** or **Larmor
frequency**, is the frequency of rotation of a charged particle or ion
as it spirals a magnetic field.

The trajectory of a charged particle acted on solely by a magnetic force
is a helix with its axis parallel to the magnetic induction. In any plane
perpendicular to the magnetic induction the particle describes a circular
orbit with gyrofrequency *qB/m*, where *q* is charge, *m* is mass, and *B* is the magnitude of magnetic induction.