Upper hybrid mode conversion and resonance excitation of Bernstein modes in ionospheric heating experiments

Abstract

We investigate mode conversion of propagating upper hybrid waves to resonantly excited nonpropagating electrostatic electron cyclotron harmonic (Bernstein) modes and show that it can explain the absence of stimulated emission of sideband electromagnetic radiation from the ionosphere in the kilohertz frequency range less than the input pump frequency when the latter is very close to or at harmonics (third and above) of the electron cyclotron frequency. The results are in good agreement with the ionospheric heating experiments conducted at Tromsø (Norway) as well as at Arecibo (Puerto Rico).