{"created":"2021-03-01T06:52:50.702562+00:00","id":33999,"links":{},"metadata":{"_buckets":{"deposit":"0ab004e5-7b90-47b4-94c8-c8243d117f66"},"_deposit":{"id":"33999","owner":"1","owners":[],"pid":{"revision_id":0,"type":"depid","value":"33999"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00033999","sets":["80:4535:5047:5048","9:504:4538:5049:5050"]},"author_link":["132577","132576"],"item_4_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"地球核内の有限振幅電磁流体振動"}]},"item_4_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1956-03-30","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"4","bibliographicPageEnd":"592","bibliographicPageStart":"583","bibliographicVolumeNumber":"33","bibliographic_titles":[{"bibliographic_title":"東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo"}]}]},"item_4_description_13":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_4_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Finite magneto-hydrodynamic oscillations of perfectly conducting fluid sphere are studied. No motion and no magnetic field are assumed at the equilibrium state. Ignoring higher spherical harmonic constituents, only the field that gives the dipole-like one outside the sphere is considered. Although it seems difficult to solve the non-linear integro-differential equations which are deduced from the fundamental equations of electromagnetism and fluid motion, a crude examination of the equations suggests that there exists a finite oscillation of a special type. The result also suggests that the earth's dynamo might perform a finite oscillation even though the small oscillations of the dynamo are unstable. In that case, it is of interest to note that one might expect reversals of the earth's magnetic field.","subitem_description_type":"Abstract"},{"subitem_description":"従来地球核内の微小振幅振動を取扱つて地磁気ダイナモの安定性を論じて来たが,この議論を有限振幅の場合に拡張した.数学的困難をさけるために,平衡状態に於ては磁場および流体運動がともに零であるとし,核外に双極子磁場としてあらわれるものにのみ着目し,それ以外の磁場は一切無視する.かくして流体運動の運動方程式およびMaxwellの基礎方程式より,磁場ならびに速度に関する非線型連立積分微分方程式を求めた.この方程式を適当な省略をほどこして解く時は,非常に簡単な場合として振動性の解が求められる.この解は磁場が正負の同符号をとり得ることを示し,振動周期は密度の自乗根と核半径に比例し初期磁場の振幅に逆比例する.もしこのような振動が実在する時には,地球磁場の逆転も起り得ることになる.実際問題としては磁場が小さい間は非電磁的流体運動による増幅作用が行われ,磁場がかなり大きくなると本論文にのべたような電磁力の作用がいちじるしくなるものと思われる.","subitem_description_type":"Abstract"}]},"item_4_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"132577","nameIdentifierScheme":"WEKO"}],"names":[{"name":"力武, 常次"}]}]},"item_4_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15083/0000033999","subitem_identifier_reg_type":"JaLC"}]},"item_4_publisher_20":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"東京大学地震研究所"}]},"item_4_source_id_10":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN00162258","subitem_source_identifier_type":"NCID"}]},"item_4_source_id_8":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"00408972","subitem_source_identifier_type":"ISSN"}]},"item_4_subject_15":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"453","subitem_subject_scheme":"NDC"}]},"item_4_text_21":{"attribute_name":"出版者別名","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute, University of Tokyo"}]},"item_4_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Rikitake, Tsuneji"}],"nameIdentifiers":[{"nameIdentifier":"132576","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-06-27"}],"displaytype":"detail","filename":"ji0334005.pdf","filesize":[{"value":"441.6 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ji0334005.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/33999/files/ji0334005.pdf"},"version_id":"89ab9810-81cc-44b0-a8b5-a8328896f831"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"Magneto-hydrodynamic Oscillations of Finite Amplitude of a Conducting Fluid Sphere","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Magneto-hydrodynamic Oscillations of Finite Amplitude of a Conducting Fluid Sphere","subitem_title_language":"en"}]},"item_type_id":"4","owner":"1","path":["5048","5050"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-05-30"},"publish_date":"2008-05-30","publish_status":"0","recid":"33999","relation_version_is_last":true,"title":["Magneto-hydrodynamic Oscillations of Finite Amplitude of a Conducting Fluid Sphere"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-19T04:58:22.010644+00:00"}