Full wave analysis of altitude profiles of auroral hiss observed by antarctic rocket.

Abstract

Electromagnetic waves in the VLF range associated with auroral hiss were observed by the S-310JA-11 and -12 rockets launched from Syowa Station into quiet auroral arcs and breakup auroras, respectively. The altitude profile of electric field intensity observed by the S-310JA-12 rocket in the frequency range less than 5kHz showed a distinct peak at an altitude of 90km. The source location of the auroral hiss has been estimated so that the observed altitude profile of the hiss intensity, particularly around the altitude of 90km, coincides with the altitude profile calculated using the full wave analysis. It was found that the auroral hiss is most likely to be generated at an altitude about 700km. The intensity of auroral hiss around the altitude of 200km at a frequency of 4kHz observed by the rocket was 4.3×10-5V/m/√Hz, which is much stronger, by about 50dB, than that of auroral hiss observed on the ground at Syowa Station. This means that the k-vector direction of auroral hiss observed on the rocket is outside the transmission cone.