Fig. 1From: Role of hard X-ray emission in ionospheric D-layer disturbances during solar flaresGreat Circle Path (GCP) between the VLF/LF stations used in the analysis and Meudon (France). Violet points indicate the sub-reflection area on the ionosphere. Blue circles indicate the transmitter location. Note that NRK, GVT (Skelton, Cumbria), GQD (Anthorn), ICV and NSY are almost aligned. The antenna is orientated to optimize their receptionBack to article page