{"created":"2023-05-15T14:37:52.247260+00:00","id":48866,"links":{},"metadata":{"_buckets":{"deposit":"818f6dcc-738c-46f7-a265-271e78718411"},"_deposit":{"created_by":1,"id":"48866","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"48866"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00048866","sets":["1"]},"author_link":["492268","492267","492266"],"item_8_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2018-05","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"116063-21","bibliographicPageStart":"116063-1","bibliographicVolumeNumber":"57","bibliographic_titles":[{"bibliographic_title":"Nuclear Fusion"}]}]},"item_8_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Using the linear gyrokinetic code LIGKA, we study the structure of the continuous spectra Ω(ρ) = ω(ρ) + iγ(ρ) of shear Alfvén waves (SAW) and ion sound waves (ISW) in a high­-beta JT­60U tokamak plasma and look for evidence of Alfvén acoustic couplings or mode conversion. Here, Ω is the complex local eigenfrequency, ρ is a radial coordinate, and we consider waves with low toroidal mode number n = 3 . We focus on the frequency range\nω[BAE] <= ω <= ω[TAE] between the beta­-induced and toroidicity­-induced Alfvén frequency gaps. The real frequencies ω(ρ) of the gyrokinetic ISW continua are remarkably similar to MHD results. The kinetic damping rates are of order −γ/ω ~ 30% for Te /Ti ≈ 1.7 , and reduce to 15% when the temperature ratio is raised to Te /Ti ≈ 4.8 . It is shown that SAW and ISW continua can be simultaneously excited with an antenna and that the global response of the\nISWs is significantly enhanced when the on­-axis beta value is raised from β0 = 1.7% to 3.6% while keeping Te /Ti > 1 . In contrast, when the ion temperature is increased such that Te /Ti ≈ 0.4 , ISW branches become undetectable in spite of higher β0 . At the same time, a large part of the SAW continuum is locally destabilized by ion temperature gradients and a set of discrete global modes was found, some of which are weakly damped or unstable and interpreted as kinetic beta-­induced Alfvén eigenmodes. It is estimated that the kinetic damping\nof such low­-n Alfvénic modes contributes much more to the anomalous bulk ion heating than the excitation of nearby ISW continua, so that Alfvén acoustic couplings in the frequency band ω[BAE] <= ω <= ω[TAE] are irrelevant within the scope of the model used.","subitem_description_type":"Abstract"}]},"item_8_relation_14":{"attribute_name":"DOI","attribute_value_mlt":[{"subitem_relation_type_id":{"subitem_relation_type_id_text":"10.1088/1741-4326/aa80fe","subitem_relation_type_select":"DOI"}}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"metadata only access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_14cb"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ビアワーゲ, アンドレアス"}],"nameIdentifiers":[{"nameIdentifier":"492266","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Lauber, Philipp"}],"nameIdentifiers":[{"nameIdentifier":"492267","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"ビアワーゲ アンドレアス","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"492268","nameIdentifierScheme":"WEKO"}]}]},"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":"journal article","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"Gyrokinetic analysis of low-n shear Alfvén and ion sound wave spectra in a high-beta tokamak plasma","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Gyrokinetic analysis of low-n shear Alfvén and ion sound wave spectra in a high-beta tokamak plasma"}]},"item_type_id":"8","owner":"1","path":["1"],"pubdate":{"attribute_name":"公開日","attribute_value":"2018-05-08"},"publish_date":"2018-05-08","publish_status":"0","recid":"48866","relation_version_is_last":true,"title":["Gyrokinetic analysis of low-n shear Alfvén and ion sound wave spectra in a high-beta tokamak plasma"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-15T23:23:28.694459+00:00"}