Stimulated Electromagnetic Emission Measurements Using the Arecibo HF System and Multiple Ground Receiver Stations

High power HF radio waves interacting with the ionosphere provide aeronomers with a unique space-based laboratory capability. Stimulated Electromagnetic Emissions (SEE) are of interest to the ionospheric community for its diagnostic purposes. Typical SEE experiments at Arecibo have focused on characterizing the parametric decay of the electromagnetic pump wave into several different wave modes such as upper and lower hybrid, ion acoustic, ion-Bernstein and electron-Bernstein.

The Probing Regions via Ionospheric Modification (PRIM) campaign in July 2019 was a multi-station effort to better characterize the artificial ionospheric disturbances created by the Arecibo HF facility. Two SEE stations were deployed during this campaign, one ~20 km from the Arecibo Observatory and one on a US Navy boat located north of Puerto Rico in the Atlantic Ocean. These dual measurements provide an insight for how the ionosphere distorts the signal through received phase and time delays. These stations were also used as diagnostics to determine how different HF excitation modes transmitted from Arecibo affected the production and characteristics of the disturbed ionospheric region.

This research is sponsored by the NRL 6.1 base program.