SPEARS Seminar: Listening to the Ionosphere: Wave Mode Identification in Electromagnetic Emissions Excited by High Power Radio Waves

Doctor Paul Bernhardt, United States Naval Research Laboratory

Thursday 22 March 2012, 1600-1700
Lecture Theatre, Charles Carter Building (A15)

Ionospheric modification with high power HF waves couples in the plasma to produce a wide spectrum of plasma waves. These waves can modulate the transmitted (pump) wave to yield sidebands in the scattered electromagnetic spectra. The full dispersion equation for a magnetized plasma in the ionosphere is solved to identify these excited modes. With this process, a large number of wave modes have been identified in the stimulated electromagnetic emission spectra obtained at the High Altitude Auroral Research Program (HAARP) facility in Alaska. Similar modes should be and have been detected with other ionospheric modification transmitters are located in Norway (EISCAT), Puerto Rico (Arecibo) and Russia (SURA). These waves are used to (1) discover the basic plasma physics of high power radio wave interactions in the ionosphere, and (2) directly observe some properties of the upper atmosphere.