[1] It shown theoretically and confirmed for the first time experimentally that the magnetic response of the lower auroral ionosphere to pulsed ionospheric HF heating depends critically on the parameter T/Th, where T is the pulse duration and Th is the time required for the electron temperature to reach its steady state value. Theoretical analysis shows that the strength and pulse shape of the ...

A comparative study of the geomagnetic and ionospheric data at equatorial and low-latitude stations in India over the 20 year period 1956±1975 is described. The reversal of the electric ®eld in the ionosphere over the magnetic equator during the midday hours indicated by the disappearance of the equatorial sporadic E region echoes on the ionograms is a rare phenomenon occurring on about 1% of t...