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Helicon waves are a type of an electromagnetic wave that is clockwise circularly polarized and propagates through a metal in a strong magnetic field with weak collisional damping.
Helicon waves are whistler waves whose frequency falls between those of ion cyclotron and the electron cyclotron, and they propagate along magnetic field lines.
Helicon waves are characterized by their nature to propagate in a bounded plasma rather than in an infinitely extended plasma, and the fact that the electron cyclotron motion does not need to be taken into account for the calculation of the dispersion equation, due to their low frequency.