Ionospheric conditions following the proton flare event of 7 July 1966 as measured at ground-based stations: II. F-region effects

The F-region response to the 7 July 1966 proton flare event, over the European and Asian regions, is characterized by a two-phase ionospheric storm, starting with a positive phase in high and medium latitudes, followed by a two-step decrease of f,F2, beginning earlier than the main phase of the geomagnetic storm. At 60 degrees geomagnetic latitude, the maximum positive phase is reached at a time 33.9 hours after the proton flare. The characteristic features of the foF2 time variation during the disturbance show a significant propagation from higher towards lower geomagnetic latitudes, and from eastern towards western geographic longitudes.