A theoretical explanation of intensitie of storm-time VLF hiss emissions observed at low latitudes

For known plas ma parameters and cons idering quasi -linear electron cyc lotron resonance instabi li ty and incoherent Cerenkov rad iation process, the intensit ies of intense storm-t ime YLF hiss emissions, observed in the low l::tti tude ground stations of Japan , are explained. Based on the intensity calcu lat ions in low latitude equatorial plane, which arc inconsistent with the observed intensit ies, the local generations by either of the above two mechani sms are ruled out. It is suggested that the emissions are due to mechanism of quasi-linear electron cyclotron resonance instability in the equatorial plane at L = 3.6 by -5 keY electrons which drift eastward fro m higher lati tudes and enter the ionosphere at a latitude higher than tha t of Moshiri (L = 1.6). These then propagate towards the observer in earth-ionosphere wave-gui de mode.