Summary: | P(論文) Some early results are presented on medium-latitude VLF/ELF emissions observed by the simultaneous measurements at the two stations in Europe during November 1978 through January 1979. The main aim of the present research is the adoption of two different kinds of direction finding systems; (i) a field-analysis direction finding, and (ii) a goniometer network, which has enabled us to locate the ionospheric exit points of different kinds of VLF/ELF emissions over a wide range in L values. The VLF/ELF emissions observed are found to be classified into four major categories; (1) plasmapause-associated VLF emissions, (2) VLF hiss in the electron slot region, (3) periodic hiss emissions, and (4) periodic VLF emissions triggered by the hiss band. The characteristics of one example from each category are described, and the mechanisms of their generation and propagation will be studied in the future. departmental bulletin paper
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