Coordinated Observations of High Power Interactions with the High Latitude Ionosphere

Abstract

The High Frequency Active Auroral Research Program (HAARP) transmitter in central Alaska changes the properties of the F-region with transmissions of high power radio waves that reflect in the ionosphere. Simultaneous measurements of radar scatter from plasma waves, radar scatter from field aligned irregularities, and radio wave spectra near the HF pump wave frequency provide a clear picture of the radio wave interactions. The HAARP F-region diagnostics are (1) Modular IJHF Ionospheric Radar (MURI), (2) Dual Auroral Radar Network (SuperDARN), and (3) Stimulated Ionospheric 1 {missions Radio Receiving Array (SIKRRA). The MUIR incoherent scatter plasma line spectra are produced by Langmuir waves driven by the HF pump. The plasma line is initially intense with a decay associated with formation of field aligned irregularities (FAFs) that absorb the electromagnetic HF before reaching the reflection altitude. Consequently the growth of SuperDARN radar backscatter from FAI is coincident with the decay of the HF induced plasma lines, the independent SIERRA diagnostic of stimulated electromagnetic emissions (SHE) measured with ground receivers show a decay of a down-shifted spectral feature associated and a formation of a weak broad continuum. The temporal history of the radar and SEE data are being analyzed to provide a complete understanding of nonlinear interactions of high power EiM wave in the ionospheric over HAARP.