Aj. Stocker et al., THE EFFECT OF ARTIFICIAL MODIFICATION IN THE E-REGION ON HF RAY-PROPAGATION, Journal of atmospheric and solar-terrestrial physics, 59(18), 1997, pp. 2435-2446
During RF heating at 4.04 MHz an increase of 5 dB in the signal streng
th of a 4.2 MHz probe wave has been observed. This is attributed to a
heater induced increase in electron density in the E region leading to
the opening up of a low angle propagation path from probe transmitter
to receiver. The geometry of the experiment is consistent with an ele
ctron density increase distributed in a torus in the E region centred
above the heater site. (C) 1997 Elsevier Science Ltd.