Investigation of Space/Ionospheric Plasma Turbulence caused by Anomalous Large-Scale Thermal Fronts

This research is aimed at investigating the possibility that large-scale anomalous heat source (e.g. heat wave event) might be capable of triggering widespread turbulence in the space/ionospheric plasma layer through the excitation of acoustic-gravity waves (AGWs). This hypothesis was motivated by the observation of intense traveling ionospheric disturbances (TIDs) over Arecibo Observatory, Puerto Rico, for several consecutive days in the summer 2006. At that time, the geomagnetic condition was relatively quiet, and there were no major earthquake, tsunami, or volcanic eruptions. However, we note that during this time period, a relatively severe and prolonged heat wave was steadily sweeping eastward across the mainland United States. These findings therefore suggest that the thermal gradients associated with the heat wave fronts are generating AGWs that could propagate through long distances to induce space plasma turbulence in the form of TIDs over an extended region.

In this HF heating experiment, we utilize a number of ground-based and satellite diagnostics (which include HF and UHF radars, as well as GPS and LEO satellites).

We aim to detect the plasma disturbances generated by the modulated heating, and to be able to distinguish it from natural ionospheric disturbances that might happen to pass overhead during the experiments. Possible contamination from naturally-occurring disturbances generally can be minimized by conducting the experiments during geomagnetically quiet times.