{"created":"2023-06-20T13:20:28.376235+00:00","id":492,"links":{},"metadata":{"_buckets":{"deposit":"2322c21c-b9ae-46e9-9d83-88d53236a3fa"},"_deposit":{"created_by":1,"id":"492","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"492"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00000492","sets":["2:427:12"]},"author_link":["8645","8647","8646"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"裴, 文兵"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ペイ, ウェンビン"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2001-03-23"}]},"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（学術）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"　　Collisionless magnetic reconnection is a fundamental process of many dynamical phenomena with a fast and impulsive energy release observed in high temperature plasmas, such as solar flares, geomagnetic substorms and tokamak disruptions. Magnetic reconnection requires some non-ideal mechanism to break down the frozen-in constraint in a weak field region, called dissipation region, and thus allows the topological change of magnetic field. This process can lead to a sudden release of stored magnetic energy into particle energy and plasma transport in a large spatial scale. The fast and impulsive reconnection in collisionless plasmas remains one of major subjects of plasma physics and at a hot issue to date. Collisionless reconnection driven by an external plasma inflow, collisionless driven reconnection, is one of the potential candidates because reconnection rate is mainly controlled by external driving conditions. Driven reconnection is a dynamical process in an open system where there exist energy inflow and outflow through its boundaries. For an open system with a constant energy supply, we would expect two ways of time evolution in collisionless driven reconnection in a long time scale, i.e., steady and intermittent ways. Only a few particle simulations have so far been carried out to investigate dynamical process of collisionless driven reconnection. However, these studies are restricted to only early growing phase because a periodic condition is used at the downstream boundaries. Thus, which way the system selects as an evolution route remains unsolved to date.<br />　　In order to to explore long time scale behavior of collisionless driven reconnection, a full open boundary model is required. We develop a new two-dimensional particle simulation model for an open system with free conditions at the downstream boundaries on the basis of the previous version. In this model, a free physical condition is used at the downstream boundary, across which particles can freely go in and out. At the upstream boundary the driving condition can be uniquely determined by an external driving electric field which is described by two key parameters, i.e., the strength E0 and the early non-uniformity scale xd. Based on the newly developed open model, long time scale evolution of collisionless driven reconnection is simulated. The simulation results reveal many new features of collisionless reconnection which help us to understand the physical processes of collisionless reconnection. In this thesis, we clarify the mechanism of collisionless driven reconnection, and the relationship between the driving conditions and the long time scale behavior of driven reconnection.<br />　　The evolution of collisionless driven reconnection depends strongly on the external driving electric field. The strength E0 controls the reconnection rate, while the scale xd controls the current layer shape and thus the magnetic field configuration. It is found that there are two regimes in the long time scale behavior of collisionless reconnection which is mainly controlled by the scale xd in our simulation parameter range, i.e., steady regime and intermittent regime. In a small xd case the system evolves toward a steady regime in which steady reconnection is realized and thus the global field topology remains unchanged. This is the first results that particle simulation discloses the existence of steady reconnection. On the other hands, in a large xd case the system evolves into an intermittent regime in which magnetic islands are frequently excited to grow near the center of the current sheet.<br />　　The physical features of the steady reconnection is investigated. The reconnection rate in the steady regime is determined by the strength of the driving electric field E0 even if reconnection would be triggered by microscopic particle dynamics. In other words, microscopic scale dynamics in the current sheet evolves so as to accommodate macroscopic scale dynamics in the surroundings. The dissipation region has two-scales structure cor- responding to both the electron dynamics and the ion dynamics. The electron dissipation region is dominated by the electron inertia effect which controls the electron flow velocity through an electrostatic field. The ion inertia effect is responsible for breaking the ion frozen-in constraint in the ion dissipation region, while the ion meandering motion plays an important role in ion dynamics which controls the spatial structures of plasma density, ion flow velocity and ion temperature. Although the current is predominantly carried by electrons, the current layer has the half-width of the ion meandering orbit scale lmi. This is because the density profile is exclusively controlled by the massive ion motion. That is,  the global dynamic process of steady magnetic reconnection is dominantly controlled by ion dynamics. The electrostatic field generated through a finite Larmor radius effect is a key to coordinate the motions of electrons and ions. It leads to electron acceleration in an equilibrium current direction in the ion dissipation region and ion heating by intensifying meandering motion. Our results are in good agreement with the recent experimental results in MRX in the aspects of current layer width and ion heating [Yamada et al., Phys. Plasmas 7, 1781 (2000), Hus et al, Phys. Rev. Lett. 84, 3859 (2000)].<br />　　The dynamical process of collisionless reconnection in the intermittent regime is studied. The intermittent behavior is found to appear due to the frequent formation of magnetic islands as a result of the excitation of an electron microscopic instability. The detailed analysis of simulation results reveals that the island growth is caused by the current increase through the electron trapping in it, and thus the instability is triggered by electron dynamics. To shed light on the island excitation mechanism in the intermittent  regime, the effect of the driving parameters E0 and xd on the current layer structure and the magnetic field configuration has been explored in the regime of steady reconnection. As E0 increases, the current layer is similarly compressed, and thus the corresponding magnetic field configuration is almost unchanged. On the contrary, as xd increases, the current layer becomes narrow and flat in shape so that the angle between the separatrices decreases. The change of the current layer structure leads to generation of a seed island with spatial size longer than the electron meandering size in the outflow direction, which is equal to the spatial size of unmagnetized electron thermal motion. This island grows up by increasing the electric current through the electron trapping in it. Thus, in a large xd case the system evolves into the intermittent regime in which magnetic islands is frequently formed near the original X point.","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523号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"数物科学研究科"}]},"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":"2000"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"PEI, Wen-Bing","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"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","filename":"甲523_要旨.pdf","filesize":[{"value":"441.1 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨 / Abstract, Screening Result","url":"https://ir.soken.ac.jp/record/492/files/甲523_要旨.pdf"},"version_id":"d5d97014-f551-4e91-a296-8843de6d9603"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲523_本文.pdf","filesize":[{"value":"3.7 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/492/files/甲523_本文.pdf"},"version_id":"1ae84a85-2da9-4861-aa21-36fb7cf900c0"}]},"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":"Long Time Scale Evolution of Collisionless Driven Reconnection in a Two-Dimensional Open System","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Long Time Scale Evolution of Collisionless Driven Reconnection in a Two-Dimensional Open System"},{"subitem_title":"Long Time Scale Evolution of Collisionless Driven Reconnection in a Two-Dimensional Open System","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["12"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"492","relation_version_is_last":true,"title":["Long Time Scale Evolution of Collisionless Driven Reconnection in a Two-Dimensional Open System"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T14:53:18.840137+00:00"}