Evidence of HF‐driven wave interactions in the ionospheric focused heating experiment

Abstract

The Ionospheric Focused Heating rocket experiment created an ionospheric hole above the Arecibo HF radiowave heater by the release of an electron‐attachment chemical. The hole served as a focusing lens for HF waves at 5.1 MHz and produced various plasma wave effects measured by onboard diagnostic instruments. In this report, we present evidence for the occurrence of plasma wave interactions driven by the HF pump at altitudes where the pump frequency is near the electron plasma frequency and one‐half the electron plasma frequency. These interaction regions are observed on the upper side of the ionospheric hole. The data suggest that the frequency and wavenumber matching requirements for coupled waves are met in these regions.