Geomagnetic conjugacy of 30‐kHz band auroral hiss emissions observed at L = 6.1

Statistical characteristics of auroral hiss emissions in the 30-kHz band were examined using the data observed simultaneously at the Syowa-Husafell conjugate pair of stations during the period of September-November 1983. The occurrence probabilities of conjugate events observed simultaneously at the two stations were almost the same in September and October and decreased during November. The nonconjugate events observed only at Syowa Station were detected more often in September. The number of nonconjugate events decreased in October and November. These phenomena were mostly observed during 1700–2300 MLT around the geographic midnight at Syowa. On the other hand, the number of nonconjugate phenomena detected only at Husafell in Iceland increased from September to November. The occurrence peaks were around 2100–0200 MLT, before geographic midnight at Husafell. From these statistical characteristics it is found that auroral hiss emission occurrences strongly depend on not only the magnetic local time but also the geographic local time and seasons, suggesting that auroral hiss emissions observed on the ground are strongly controlled by the sunlit effects in the topside ionosphere.

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