The statistical analyses of intensity and occurrence-frequency of auroral kilometric radiation (AKR) observed by the plasma wave and sounder experiment (PWS) onboard the Akebono (EXOS-D) satellite have been carried out for the seven-year period from March 1989 to February 1996. The results show clear seasonal variations of AKR intensity and occurrencefrequency both in the northern and southern polar regions. AKR exhibits an increase in the intensity and occurrence-frequency of intense emissions in the winter polar regions; thus there is a distinct north-south asymmetry of AKR. This tendency of asymmetry feature of AKR emission sources becomes more prominent in the high frequency range. These results have given strong confirmation to the GEOTAIL observation reported by Kasaba et al. . The origin of this asymmetry of AKR emissions are plausibly related with the seasonal dependence of the acceleration processes of the auroral electrons as has been suggested by Newell et al. .
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