Relation between Hertz Range Artificial Pulsations and the Dynamics of the Auroral Electrojet: Experiment at the SPEAR Facility

We have analyzed the artificial pulsations detected in several cases in the hertz range in terms of the eastern electrojet dynamics. The pulsations were detected in 30% cases of pulse HF wave impact on the ionosphere during an experiment on modulated ionosphere heating at the Space Plasma Exploration by Active Radar (SPEAR) facility (Spitsbergen Archipelago) in November 2013. The pulsations occur when the polar edge of the eastern electrojet approaches the assumed region of influence on the ionosphere due to the northward drift of the electrojet or its extension with increased intensity. The pulsations vanish when the electrojet moves away from the influenced region, drifting southward. The beginning of pulsations is delayed by several minutes with respect to the starting of the HF transmitter. The pulsations are observed only in one of the horizontal components of the geomagnetic field at a distance of 50 km from the SPEAR facility, and they vanished at a distance of about 1300 km.