@article{oai:nagoya.repo.nii.ac.jp:00019710, author = {竹内, 利雄 and 石川, 晴治 and 高木, 増美 and TAKEUCHI, Toshio and ISHIKAWA, Haruzi and TAKAGI, Masumi}, issue = {1-2}, journal = {空電研究所報告}, month = {Mar}, note = {In this paper the beginning stage of a ground discharge is investigated mainly on the record of mill type field meter and the following results are obtained. It has reported by Clarence and Malan that a ground discharge usually has the "preliminary discharge" - the B field change according to their notation -, which takes place between negative charge in thundercloud and positive charge in lower part of it and leads to a return stroke. In more than 50% cases of the ground discharges recorded by authors observations, they each have a cloud discharge before the preliminary discharge. The cloud discharge neutralizes a part of main negative charge in the cloud and its duration is roughly within 500 ms. In some period of a thunder-storm, this type of ground discharge predominates over the cloud-discharge-less type, but in an other period of it, it reverses. It seems probable to infer that the cloud discharge discussed in this paper concerns a stage in a thunder-storm activity.}, pages = {1--6}, title = {雷放電の研究(第2報) : 落雷に先行する放電}, volume = {9}, year = {1959} }