SOME CHARACTERISTICS OF THE LOWER HYBRID RESONANCE NOISE BANDS OBSERVED BY THE ALOUETTE I SATELLITE

An investigation has been made of the occurrence as a function of latitude and time of lower hybrid resonance (LHR) noise bands as recorded during 1963 and 1964 by the very-low-frequency receiver aboard the Alouette I satellite. Two different types of LHR noise are observed—polar and mid-latitude. Polar LHR noise bands, with the maximum frequency of occurrence at about 75° invariant latitude, are observed approximately one half of the time throughout the year and during both night and day. Mid-latitude LHR noise bands have a maximum frequency of occurrence at about 55° and are observed mainly during the months of June–October and primarily at night. The differences in appearance and occurrence of these two types of LHR noise suggest different excitation mechanisms.