From Biology-Online Dictionary | Biology-Online Dictionary


(Science: physics) A wave in a plasma which propagates parallel to the magnetic field produced by currents outside the plasma at a frequency less than that of the electron cyclotron frequency, and which is circularly polarized, rotating in the same sense as the electrons in the plasma (about the magnetic field), also known as the electron cyclotron wave.

Whistlers are so-named because of their characteristic descending audio-frequency tone, which is a result of the dispersion relation for the wave (higher frequencies travel somewhat faster).

This tone was frequently picked up during world war I by large ground-loop antennas (which were actually being used to spy on enemy field telephone signals).