Larmor Precession

Larmor precession is the steady wobble of a tiny magnet, such as an atomic nucleus or an electron’s spin, around an applied magnetic field. When a magnetic moment finds itself in a uniform external field it experiences a torque that makes it rotate, much like a spinning top tilts and circles under gravity. The rate of this circling is called the Larmor frequency; it is directly proportional to the strength of the field and depends on a constant specific to the type of particle, known as its gyromagnetic ratio. In practice the moment traces out a cone‑shaped path while maintaining its angle with respect to the field.