{"_buckets": {"deposit": "8186b4e2-0936-4535-a9a0-5bcebecbffc0"}, "_deposit": {"created_by": 21, "id": "1418", "owners": [21], "pid": {"revision_id": 0, "type": "depid", "value": "1418"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00001418", "sets": ["12"]}, "author_link": ["0", "0", "0"], "item_1_biblio_info_21": {"attribute_name": "書誌情報（ソート用）", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "2009-03-24", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "李, 斌"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "リ, ビン"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_date_granted_11": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "2009-03-24"}]}, "item_1_degree_grantor_5": {"attribute_name": "学位授与機関", "attribute_value_mlt": [{"subitem_degreegrantor": [{"subitem_degreegrantor_name": "総合研究大学院大学"}]}]}, "item_1_degree_name_6": {"attribute_name": "学位名", "attribute_value_mlt": [{"subitem_degreename": "博士（理学）"}]}, "item_1_description_1": {"attribute_name": "ID", "attribute_value_mlt": [{"subitem_description": "2009018", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": "　Magnetic reconnection process has been investigated over half a century. Still, some\u003cbr /\u003eproblems remain unsolved. The typical one is the onset problem, namely, how fast\u003cbr /\u003ereconnection is initiated. Another important issue is how huge magnetic energy is\u003cbr /\u003econverted to plasma energies in a short time scale. \u003cbr /\u003e　Collisionless reconnection sets in when the current sheet is compressed as thin as\u003cbr /\u003eion kinetic scale by the external driving sources. After experiencing some transient\u003cbr /\u003ephase the system can relax to a steady state in which reconnection rate balances the\u003cbr /\u003einflow rate of magnetic flux from the external region, and then a new equilibrium\u003cbr /\u003estate is realized there through kinetic processes. Accordingly, driven reconnection\u003cbr /\u003emodel is applied to study physical processes of collisionless reconnection in a steady\u003cbr /\u003estate in this thesis. \u003cbr /\u003e　The research focus of this thesis is on the electron force balance in the electron\u003cbr /\u003edissipation region (EDR) where electron frozen-in condition is broken due to micro-\u003cbr /\u003escopic electron kinetic effect, and how energy conversion process takes place there, \u003cbr /\u003eespecially from magnetic energy to that of electrons, in steady collisionless driven\u003cbr /\u003ereconnection. \u003cbr /\u003e　The simulation domain is implemented on 2D and 3D rectangular open systems, \u003cbr /\u003eand a one-dimensional Harris equilibrium is employed as an initial condition. Plasma\u003cbr /\u003einflow enters the simulation domain in y direction and the outflow leaves it in x\u003cbr /\u003edirection in our coordinate system. In order to supply plasma inflow into the system\u003cbr /\u003eand initiate reconnection, a driving electric field, which is stronger within the input\u003cbr /\u003ewindow around x = 0 at initial stage, is imposed in z direction at the upstream\u003cbr /\u003eboundary. Plasma outflow goes through the downstream boundary at x = \u0026plusmn;x\u003csmall\u003eb\u003c/small\u003e , \u003cbr /\u003ewhich is open for plasma particles and electromagnetic fields. In the 3D simulation\u003cbr /\u003ecase, the boundary conditions at z= \u0026plusmn; z\u003csmall\u003eb\u003c/small\u003e along the z axis are periodic. The following\u003cbr /\u003esummary focuses mainly on the physical processes of steady reconnection based on\u003cbr /\u003ethe 3D simulation results. \u003cbr /\u003e　It is found that a dissipation region with an enhanced electron current density\u003cbr /\u003eextends from the reconnection point toward the downstream region, and a long thin\u003cbr /\u003eEDR with dual structure is formed in a steady state. We show that the force balance\u003cbr /\u003ein the direction of the reconnection electric field (the z direction) is quite different\u003cbr /\u003efrom that in the upstream direction (the y direction) in the EDR\u003cbr /\u003e　In the z direction, the Lorentz force balances the electric force just outside the\u003cbr /\u003eEDR, and then decreases rapidly inside the EDR and vanishes at the reconnection\u003cbr /\u003epoint. The electron inertia term has a local peak around the electron skin depth, but\u003cbr /\u003eit is canceled out by the electron pressure tensor term. Only pressure tensor term\u003cbr /\u003esustains the electric field at the reconnection point, i.e., reconnection electric field.\u003cbr /\u003e　Because the driving electric field works mainly on magnetized electrons inside\u003cbr /\u003eion dissipation region and pushes them into the EDR, strong electrostatic field is\u003cbr /\u003egenerated through the charge separation. Thus, a new force balance state is realized\u003cbr /\u003ein the upstream direction in the steady state. Although the pressure gradient force\u003cbr /\u003ebalances the Lorentz force in the Harris equilibrium, the electrostatic force balances\u003cbr /\u003ethe Lorentz force in the y direction in the new equilibrium state. \u003cbr /\u003e　The energy conversion process inside the EDR is also studied intensively. Ac-\u003cbr /\u003ecording to the force balance in the upstream direction it is expected that magnetic\u003cbr /\u003eenergy is effectively converted to electron kinetic or thermal energy in a short time\u003cbr /\u003escale since only electron dynamics is dominant there. \u003cbr /\u003e　We show that spatial variation of electron kinetic energies in the downstream\u003cbr /\u003edirection is quite different from that in the upstream direction, which is deeply related\u003cbr /\u003eto the dual structure of the EDR along the downstream direction. Electron inflow\u003cbr /\u003ekinetic energy drops quickly as electrons come into the EDR in the upstream direction, \u003cbr /\u003ewhile only z component of electron kinetic energy increases there through the electron\u003cbr /\u003eacceleration by strong reconnection electric field in the EDR. \u003cbr /\u003e　In the downstream direction, z component of electron kinetic energy decreases as\u003cbr /\u003ethey move away from the reconnection point, and it finally drops to a constant at\u003cbr /\u003ethe edge of the inner structure of the EDR. On the other hand, outflow component\u003cbr /\u003eof electron kinetic energy increases and reaches its maximum around the edge of\u003cbr /\u003ethe inner structure of the EDR. It is also found that total electron kinetic energy\u003cbr /\u003eis almost conserved in the inner structure region of the EDR, and thus the electron\u003cbr /\u003ekinetic enerry is converted from the z component to its outflow component by the\u003cbr /\u003eLorentz force. \u003cbr /\u003e　We have clarified two important physical processes controlled by electron dynamics\u003cbr /\u003ein steady collisionless driven reconnection, i.e., the relaxation into a new equilibrium\u003cbr /\u003estate in upstream direction and effective conversion from magnetic energy to electron\u003cbr /\u003eone in the EDR. Electron dynamics manifests itself in two aspects; the first is that\u003cbr /\u003econtinuous in-place electron inflow enhances strong electrostatic field, and the second\u003cbr /\u003eis that current density is mainly sustained by z directed electron motion accelerated by\u003cbr /\u003ereconnection electric field. Thus, the new force balance between electrostatic force and\u003cbr /\u003eLorentz force associated with enhanced current density is realized in the steady state. \u003cbr /\u003eFurthermore, strong electron current density provides a path to convert magnetic\u003cbr /\u003eenergy to electron energy in the EDR through the interaction between particles and\u003cbr /\u003eelectric field. \u003cbr /\u003e", "subitem_description_type": "Other"}]}, "item_1_description_7": {"attribute_name": "学位記番号", "attribute_value_mlt": [{"subitem_description": "総研大甲第1226号", "subitem_description_type": "Other"}]}, "item_1_select_14": {"attribute_name": "所蔵", "attribute_value_mlt": [{"subitem_select_item": "有"}]}, "item_1_select_16": {"attribute_name": "複写", "attribute_value_mlt": [{"subitem_select_item": "複写不可"}]}, "item_1_select_17": {"attribute_name": "公開状況", "attribute_value_mlt": [{"subitem_select_item": "要旨のみ公開"}]}, "item_1_select_8": {"attribute_name": "研究科", "attribute_value_mlt": [{"subitem_select_item": "物理科学研究科"}]}, "item_1_select_9": {"attribute_name": "専攻", "attribute_value_mlt": [{"subitem_select_item": "10 核融合科学専攻"}]}, "item_1_text_10": {"attribute_name": "学位授与年度", "attribute_value_mlt": [{"subitem_text_value": "2008"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "LI, Bin", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "0", "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": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 0, "filename": "甲1226_要旨.pdf", "filesize": [{"value": "315.2 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 315200.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/1418/files/甲1226_要旨.pdf"}, "version_id": "63391d79-be09-48d5-af41-1ef954bba68f"}]}, "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": "thesis", "resourceuri": "http://purl.org/coar/resource_type/c_46ec"}]}, "item_title": "Electron Dynamics in Steady Collisionless Driven Reconnection", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "Electron Dynamics in Steady Collisionless Driven Reconnection"}, {"subitem_title": "Electron Dynamics in Steady Collisionless Driven Reconnection", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "21", "path": ["12"], "permalink_uri": "https://ir.soken.ac.jp/records/1418", "pubdate": {"attribute_name": "公開日", "attribute_value": "2010-03-24"}, "publish_date": "2010-03-24", "publish_status": "0", "recid": "1418", "relation": {}, "relation_version_is_last": true, "title": ["Electron Dynamics in Steady Collisionless Driven Reconnection"], "weko_shared_id": -1}