Auroral activity caused by high-power radioemission from the SURA facility

International audienceA series of experimental modifications of the ionosphere in the HF range, performed at the SURA facility base, together with optical measurements onboard the International Space Station (ISS), indicated that such impacts on the ionosphere are effective when the facility operational frequency is higher than the critical plasma frequency (for the main ionospheric F2 layer). The experimental measurements were supported by measurements at ground-based observatories, ISS, and the Demeter and GPS satellites. The analysis results of the entire data set are presented. The ray HF radio tracing for the experiment of October 2, 2007, has been calculated, and it has been indicated that the ionosphere to the north of the facility up to 60°–62° N latitudes was irradiated by the facility beam (the effects of ray redistribution and refocusing) due to refraction on the gradient of the F2 layer critical frequencies. An analysis of the ground-based and satellite measurements (both in the vicinity of a heater and in the magnetically conjugate region) indicates that it is possible to trigger a substorm in experiments with the Sura heating facility

On the possibility of localization of a substorm by using the “Sura” heating facility

International audienceWe present the results of analysis of helio-geophysical conditions for the experiments performed in 2007-2010 to study modification of the ionosphere by high-power radio emission of the “Sura” heating facility. The feature of the experiments is that the operating frequency of the facility exceeded the upper-hybrid frequency for the F2 layer maximum in the ionosphere. All the experiments were performed in the local-time sector of the Harang discontinuity (i.e., from 21:00 to 00:00, local time) to ensure the most probable influence of the facility operation on the onset of natural processes in the subauroral region of the ionosphere. At least two experiments were found to demonstrate that the observed substorm activity in the region of the modification produced by the facility could be stimulated by its operation. The results of the ground- and satellite-based measurements, both in the vicinity of the “Sura” facility and in the magnetically conjugate region, confirm the conclusion about the possibility of substorm localization by this facility