Inchorent Cherenkov radiation in the magnetosphere and the ground observations of VLF hiss

In this paper we calculate the minimum enhancement factors required to trap the VLF energy radiated by the energetic particles in the incoherent Cerenkov mode. The magnetospheric model chosen is the same as that used by T. S. Jorgensen (1968) in his attempt to account for the observed power fluxes of 'auroral' hiss in terms of the incoherent Cerenkov radiation. Our research yields values for the peak to valley ratios of electron density inhomogeneities that must be present at various heights in the magnetosphere to guide the incoherent Cerenkov radiation toward the ground. It is also pointed out that, at frequencies for which at some height the LHR frequency is encountered, the spectral densities of incoherent Cerenkov radiation reaching the ground would be less than those calculated by Jorgensen.