This complex of particles and fields supports a wide variety of wave phenomena.
Waves in plasmas can be classified as electromagnetic or electrostatic according to whether or not there is an oscillating magnetic field.
An electromagnetic wave, in contrast, must have a transverse component, but may also be partially longitudinal.
Only rarely, e.g. in the lower hybrid oscillation, will a mode depend on both the electron and the ion mass.
The various modes can also be classified according to whether they propagate in an unmagnetized plasma or parallel, perpendicular, or oblique to the stationary magnetic field.