Incoherent Cerenkov radiation as the source of auroral and polar hiss emissions

Abstract

For known plasma parameters and observed energetic electron spectra, detailed power calculations are carried out under incoherent Cerenkov radiation mechanism for auroral and polar VLF hiss emissions to confirm their generation mechanism. The results indicate a discrepancy of about an order of magnitude between the calculated and observed peak

power intensities. The precipitating electrons having energy of the order of a few tens of electron volt radiating incoherently in Cerenkov mode seem to be the fundamental sources of these emissions, which are further amplified probably by electron cyclotron resonance instability mechanism involving energetic electrons up to the observed power levels during their downward propagation from the source region.