Generation of terrestrial kilometric radiation by a beam-driven electromagnetic instability

A beam-driven electromagnetic instability which operates in the top side ionosphere in the presence of ion wave turbulence is suggested as a possible explanation of terrestrial kilometric radiation. Theoretical estimates of the central frequency and bandwidth of radiation produced in this way are consistent with observations. In its simplest form the instability mechanism leads to a spectrum of kilometric radiation which propagates primarily in the left ordinary mode as it leaves the source region.