Interpretation of auroral hiss measured on OGO 2 and at Byrd Station in terms of incoherent Cerenkov Radiation

A wideband noise known as auroral hiss is observed at very low and low frequencies at ground-based stations and on satellites at high magnetic latitudes. Several attempts have been made to explain this noise as incoherent Cerenkov radiation from energetic particles in the magnetosphere, but the conclusions were all negative, as the calculated power was several orders of magnitude below the observed power. The results of recent observations of auroral hiss and of the low-energy electrons with which this noise is strongly correlated suggest that unrealistic models were used in earlier calculations of the total power generated in the magnetosphere by an incoherent Cerenkov process. Therefore it is considered worthwhile to study the Cerenkov radiation again. This paper discusses a model for a region in space in which the auroral hiss is believed to be generated. It is shown that the total power generated in this region is comparable to the observed power, and it is concluded that auroral hiss may be generated by incoherent Cerenkov radiation from electrons with energies of the order of 1 kev.