Global Distribution of Power Line Harmonics Radiation and Natural VLF Emission Observed by the Ohzora Satellite

The global distribution of the electric field intensities of the power line harmonics radiation (PLHR) in the topside ionosphere has been measured by the on board instrument of the satellite "OHZORA". This observation started June 1st, 1984 and continues until today. The observation results show several interesting distribution characteristics of PLR over the world. (1) The largest emissions of PLHR were observed around the northern American continent such as; northern British Columbia, Alberta, Manitoba, Illinois, Michigan, Quebec and north-eastern U.S. (2) The second largest values were observed around northern Europe, such as; U.K., Germany, east part of the U.S.S.R., Moscow area and along the northern coast of the U.S.S.R.. These noisy areas are spread along the northern auroral oval and this explains the source mechanism of PLHR. (3)The authors found new strong natural VLF noise emission at geomagnetical southern Atlantic anomaly region. The authors present the observation results in this paper.