Gyromagnetic Frequency

the frequency of revolution of a free electron (or ion) in an ionized gas (plasma) about the lines of force of a constant magnetic field. The charged particle, moving with a constant velocity V directed at right angles to the magnetic field H₀, is acted upon by the Lorentz force:

where e is the charge of the electron and c is the speed of light. Under the action of the centripetal force F ⊥ V the particle moves along a circular path, in which case its revolution frequency is independent of its velocity but is determined by the mass of the particle m and by the magnitude of the magnetic field H₀:

The gyromagnetic frequency of the earth’s ionosphere is ~1.4 MHz, whereas that of the sun’s corona is ~10⁴ MHz.

The gyromagnetic frequency plays an important role in the area of the propagation of electromagnetic waves in plasma placed in a constant magnetic field, particularly in the propagation of radio waves in the ionosphere.