{"_buckets": {"deposit": "87c4600a-11a5-4cf0-b47a-7435204b700d"}, "_deposit": {"created_by": 21, "id": "2160", "owners": [21], "pid": {"revision_id": 0, "type": "depid", "value": "2160"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00002160", "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": "2010-09-30", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "周, 航宇"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "ツォウ, ハンギュウ"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_date_granted_11": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "2010-09-30"}]}, "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": "2010511", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": "　　　Impurity control is significantly important to reduce substantial power loss and to achieve high performance plasmas in controlled nuclear fusion research.　Effective ion charge, Z\u003csmall\u003eeff\u003c/small\u003e, is a key parameter to characterize the impurity contents in fusion plasmas andthe radial distribution gives clear information on the impurity transport. The Z\u003csmall\u003eeff\u003c/small\u003e value hasbeen observed using bremsstrahlung continuum in high-temperature plasmas. A Z\u003csmall\u003eeff\u003c/small\u003ediagnostic system based on a visible spectrometer has been newly designed and constructedinstead of an old interference filter system in Large Helical Device (LHD) to eliminate lineemissions and to obtain Z\u003csmall\u003eeff\u003c/small\u003e in low-density plasmas. An astigmatism-corrected Czerny-Turner-type visible spectrometer coupled with a charge coupled device (CCD) has beeninstalled with a 44-channel optical fiber array to detect the visible bremsstrahlungcontinuum profile in LHD. The diagnostic system has been absolutely calibrated with astandard tungsten lamp and an integrated sphere to analyze the visible bremsstrahlungcontinuum at 53Onm quantitatively.\r\n　　　A full vertical bremsstrahlung profile (-0.6m\u0026le;Z\u0026le;0.6m) has been successfullyobserved for horizontally elongated plasma cross section in both discharges using H\u003csmall\u003e2\u003c/small\u003e gas-puffing at normal density range (n\u003csmall\u003ee\u003c/small\u003e\u0026le;10\u003csup\u003e14\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003e)and solid H\u003csmall\u003e2\u003c/small\u003e multi-pellet injection atextremely high-density range (n\u003csmall\u003ee\u003c/small\u003e\u0026ge;10\u003csup\u003e14\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003e). The line emissions are entirely eliminatedfrom the signal due to the high spectral resolution with which the bremsstrahlungcontinuum can be clearly separated from spectral lines, whereas nonuniformbremsstrahlung emission originating in the ergodic layer is indentified in the radial profilefor the normal discharges with outwardly shifted magnetic axis configurations (R\u003csmall\u003eax\u003c/small\u003e\u003e3.60m).At present, the lower half of the vertical bremsstrahlung profile (-0.6m\u0026le;Z\u0026le;0m) isapplicable to the Z\u003csmall\u003eeff\u003c/small\u003eprofile analysis for the gas-puff discharges in inwardly shiftedmagnetic axis configurations (R\u003csmall\u003eax\u003c/small\u003e\u0026le;3.6Om). On the contrast the vertical bremsstrahlungprofile measured from the pellet discharges is fully available for the Z\u003csmalll\u003eeff\u003c/small\u003e profile analysis inall the magnetic axis configurations because the plasma edge boundary shrank in the high-density operation and the nonuniform bremsstrahlung emission disappeared.\r\n　　　Local bremsstrahlung emissivity profile has been derived from the verticalbremsstrahlung profile as a function of normalized minor radius, \u003ci\u003ep\u003c/i\u003e, through Abel inversiontaking finite β-effect into account. Errors in the calculation due to the magnetic surfacedistortion have been examined with uncertainty of the edge plasma boundary. The resultindicates that determination of the normalized minor radius for each observation chordgives the largest influence on the error estimation rather than the chord lengthdetermination. Thus, the Z\u003csmall\u003eeff\u003c/small\u003e profile has been calculated from the radial bremsstrahlungemissivity profile by considering the temperature and density profiles in a wide densityrange of 3.0\u0026le;n\u003csmall\u003ee\u003c/small\u003e\u0026le;30×l0\u003csup\u003e13\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003e and for a variety of density profiles. The Z\u003csmall\u003eeff\u003c/small\u003e valuesmeasured in the present system are checked by neutral-beam-heated discharges with H\u003csmall\u003e2\u003c/small\u003e andC pellet injections, in which the Z\u003csmall\u003eeff\u003c/small\u003e values should be close to 1 and 6, respectively. Theresult shows a good agreement between the measurement and the estimation. The line-averaged Z\u003csmall\u003eeff\u003c/small\u003e value decreases from 3.8 to 1.4 as the density varies from 3 to 9×10\u003csup\u003e13\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003einthe gas-puff discharges with R\u003csup\u003eax\u003c/sup\u003e:3.6m, while it keeps a constant value close to 1.0 fordensity range of 9 to 30×10\u003csup\u003e13\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003e in the pellet discharges with R\u003csmall\u003eax\u003c/small\u003e3.85m. The Z\u003csmall\u003eeff\u003c/small\u003e profileshave been extensively analyzed in the LHD discharges. As a result, it is found that the Z\u003csmall\u003eeff\u003c/small\u003eprofiles becomes generally flat in helical plasmas even if the density profile is changed topeaked, flat or hollow one. It indicates that the impurity partial pressure is radially constantto the electron or ion pressure.\r\n　　　Total bremsstrahlung radiation has been studied from the visible bremsstrahlungprofile by integrating over the whole energy region and plasma volume. The totalbremsstrahlung radiation is correlated with several plasma parameters for the gas-puff andpellet discharges. It is found that the total bremsstrahlung radiation quickly increases inproportion to the square of the density for the pellet discharges, while it is roughly constantagainst the density in the gas-puff discharges. The total radiation loss is entirely dominatedby the total bremsstrahlung radiation in the high-density pellet discharges. The ratio of thetotal bremsstrahlung radiation to the total input power only ranges in 3-10% in the gas-puffdischarge. However, the ratio starts to increase with the density in the pellet discharges andreaches 40% at n\u003csmall\u003ee\u003c/small\u003e=30×10\u003csup\u003e13\u003c/sup\u003ecm\u003csup\u003e-3\u003c/sup\u003e. Flat Z\u003csmall\u003eeff\u003c/small\u003e profiles are also found not only in the gas-puffdischarges but also in the pellet discharges. It strongly suggests that the impurityaccumulation is not occurred in the pellet discharges of LHD.\r\n　　　The Z\u003csmall\u003eeff\u003c/small\u003e profile diagnostics based on the visible bremsstrahlung in LHD has oftenbecome difficult because of the presence of the nonuniform visible bremsstrahlungemissions originating in the edge ergodic layer. For solving this problem, an alternativeapproach to the Z\u003csmall\u003eeff\u003c/small\u003e profile diagnostics using a space-resolved flat-field extreme ultraviolet(EUV) spectrometer has been newly adopted to detect the bremsstrahlung continuum in theEUV wavelength range of 7.0-7.5nm. The EUV bremsstrahlung intensity profiles havebeen measured and checked for all the magnetic configurations in LHD. It is found that thenonuniform bremsstrahlung emission can be entirely eliminated by use of the EUVbremsstrahlung. As a result, the Z\u003csmall\u003eeff\u003c/small\u003e profile has been successfully measured for most ofdischarges regardless of magnetic field structures of the ergodic layer which can be usuallycontrolled by the magnetic axis shift in the range of 3.5\u0026le;R\u003csmall\u003eax\u003c/small\u003e\u0026le;4.1m. The Z\u003csmall\u003eeff\u003c/small\u003e profilesmeasured in the EUV range are compared with those measured in the visible range forinwardly shifted contigurations (R\u003csmall\u003eax\u003c/small\u003e\u0026le;3.60m).The result is in good agreement between thetwo Z\u003csmall\u003eeff\u003c/small\u003e profiles. It verifies that the use of the EUV bremsstrahlung continuum is a novelway for the Z\u003csmall\u003eeff\u003c/small\u003e diagnostics in toroidal plasmas with such nonuniform bremsstrahlungernissions at the plasima edge. Typical analysis on the EUV bremsstrahlung also shows afairly flat Z\u003csmall\u003eeff\u003c/small\u003e profile with error bars of ±14% in the outwardly shifted configuration ofR\u003csmall\u003eax\u003c/small\u003e=3.75m at which the Z\u003csmall\u003eeff\u003c/small\u003e profile diagnostics is not available from the visiblebremsstrahlung measurement.", "subitem_description_type": "Other"}]}, "item_1_description_18": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_description": "application/pdf", "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1375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": "印刷物から複写可"}]}, "item_1_select_17": {"attribute_name": "公開状況", "attribute_value_mlt": [{"subitem_select_item": "全文公開可"}]}, "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": "2010"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "ZHOU, Hangyu", "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1375_要旨.pdf", "filesize": [{"value": "456.3 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 456300.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/2160/files/甲1375_要旨.pdf"}, "version_id": "966ecfe2-f721-4a65-867a-95e4ebb21267"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 1, "filename": "甲1375_本文.pdf", "filesize": [{"value": "4.1 MB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 4099999.9999999995, "url": {"label": "本文", "url": "https://ir.soken.ac.jp/record/2160/files/甲1375_本文.pdf"}, "version_id": "e519e0b3-cde6-4242-8e25-cc933a326d0c"}]}, "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": "A study of spatial structures of bremsstrahlung continuum and Zeff based on visible spectroscopy in LHD", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "A study of spatial structures of bremsstrahlung continuum and Zeff based on visible spectroscopy in LHD"}, {"subitem_title": "A study of spatial structures of bremsstrahlung continuum and Zeff based on visible spectroscopy in LHD", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "21", "path": ["12"], "permalink_uri": "https://ir.soken.ac.jp/records/2160", "pubdate": {"attribute_name": "公開日", "attribute_value": "2011-06-03"}, "publish_date": "2011-06-03", "publish_status": "0", "recid": "2160", "relation": {}, "relation_version_is_last": true, "title": ["A study of spatial structures of bremsstrahlung continuum and Zeff based on visible spectroscopy in LHD"], "weko_shared_id": -1}