LHR band emissions at mid-latitude and their relationship to ionospheric ELF hiss and relativistic electrons

Abstract

Abstract. LHR band emissions observed at mid-latitude were investigated using data from the EXOS-C (Ohzora) satellite. A typical feature of the LHR band emissions is a continuous banded structure without burst-like and cut-off features whose center frequency decreases as the satellite moves to higher latitudes. A statistical analysis of the occurrence characteristics of the phenomena showed that midlatitude LHR emissions are distributed inside the plasmapause during magnetically quiet periods, and the poleward boundary of the emission region moves to lower latitudes as the magnetic activity increases. The altitude distribution of the waves suggests that the propagation in the LHR duct formed horizontally in the mid-latitude upper-ionosphere. The emission is closely related to the occurrence of ionospheric ELF hiss. It is also shown that LHR emissions are commonly observed in the slot region of the radiation belt, and they sometimes accompany the enhancement of the ionospheric electron temperature. The generation of the LHR band emissions is discussed based on the observed characteristics.

DEMETER Observations of EM Emissions Related to Thunderstorms

“…This noise was first observed in the sixties by the Canadian satellite Alouette 1 Smith 1964, 1965). Its updated characteristics can be found in Shklyar and Washimi (1994) and Morioka et al (2005) and references therein. The LH frequency is clearly seen on the figure: at 10:35:32 UT this frequency is roughly equal to 14 kHz and decreases slowly with time (12 kHz at 10:37:30 UT).…”