Collaborative experiments by Akebono satellite, Troms⊘ ionospheric heater, and European incoherent scatter radar

Joint experiments using the Akebono satellite and the ionospheric heating facility and European incoherent scatter radar near Troms⊘ were carried out in November 1990 and February 1991. In these experiments, Troms⊘ HF transmissions were amplitude modulated at frequencies of 2.5 and 4.0 kHz. Signals radiated from the polar electrojet (PEJ) antenna in the heated ionosphere at these VLF frequencies were detected for five passes out of seven passes of the semipolar orbiting Akebono satellite. A ground-based observation of the VLF radiation from the PEJ was made in the November campaign at Lycksele in Sweden, 554 km south of the heating facility. Measurements of electron density profiles and dc electric fields in the ionosphere were carried out by the EISCAT incoherent scatter radar [Folkestad et al., 1983] located in the vicinity of the ionospheric heater. The results of the experiments are compared with those obtained by ray tracing and full-wave analyses.