After several hours of discharge cleaning, it has been observed that the decay time of the water‐vapor partial pressure changes from one well defined value to another. A long decay time observed in the later phase can be interpreted as a result of a slow deoxidization rate of chromium oxide, which may dominate the cleaning process in this phase. Optimization of the electron density for the cleaning is discussed, comparing the experimental results on density dependence of the water‐vapor partial pressure with a result based on a zero‐dimensional calculation for particle balance. One of the essential points for effective cleaning is found to be raising the electron density of the plasma high enough that the dissociation loss rate of H2O is as large as the sticking loss rate. A density as high as 1011 cm−3 is required for a clean surface condition where sticking probability is presumed to be around 0.5.
{"title":"Study of Discharge Cleaning Process in JIPP T-II Torus by Residual Gas Analyzer","authors":"N. Noda, S. Hirokura, Y. Taniguchi, S. Tanahashi","doi":"10.1116/1.572035","DOIUrl":"https://doi.org/10.1116/1.572035","url":null,"abstract":"After several hours of discharge cleaning, it has been observed that the decay time of the water‐vapor partial pressure changes from one well defined value to another. A long decay time observed in the later phase can be interpreted as a result of a slow deoxidization rate of chromium oxide, which may dominate the cleaning process in this phase. Optimization of the electron density for the cleaning is discussed, comparing the experimental results on density dependence of the water‐vapor partial pressure with a result based on a zero‐dimensional calculation for particle balance. One of the essential points for effective cleaning is found to be raising the electron density of the plasma high enough that the dissociation loss rate of H2O is as large as the sticking loss rate. A density as high as 1011 cm−3 is required for a clean surface condition where sticking probability is presumed to be around 0.5.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"1 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"1982-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86910021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Kamimura, D. Barnes, J. Leboeuf, T. Tajima, Y. Abe
A second-order accurate, direct method for the simulation of magnetized, multi-dimensional plasmas is developed. A time decentered particle push is combined with the direct method for implicit plasma simulation to include finite sized particle effects in an absolutely stable algorithm. A simple iteration (renormalized Poisson equation) is used to solve the field corrector equation. Details of the two-dimensional, electrostatic, constant magnetic field, periodic case are given. Numerical results for ion-acoustic fluctuations and for an unstable gravitational interchange confirm the accuracy and efficacy of the method applied to low-frequency plasma phenomena.
{"title":"Implicit-particle simulation of magnetized plasmas","authors":"T. Kamimura, D. Barnes, J. Leboeuf, T. Tajima, Y. Abe","doi":"10.2172/6831183","DOIUrl":"https://doi.org/10.2172/6831183","url":null,"abstract":"A second-order accurate, direct method for the simulation of magnetized, multi-dimensional plasmas is developed. A time decentered particle push is combined with the direct method for implicit plasma simulation to include finite sized particle effects in an absolutely stable algorithm. A simple iteration (renormalized Poisson equation) is used to solve the field corrector equation. Details of the two-dimensional, electrostatic, constant magnetic field, periodic case are given. Numerical results for ion-acoustic fluctuations and for an unstable gravitational interchange confirm the accuracy and efficacy of the method applied to low-frequency plasma phenomena.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"69 1","pages":"217-238"},"PeriodicalIF":0.0,"publicationDate":"1982-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88953591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"RF-Assisted Current Startup in the Fusion Engineering Device (FED)","authors":"T. Kammash","doi":"10.2172/5119789","DOIUrl":"https://doi.org/10.2172/5119789","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"37 1","pages":"555-582"},"PeriodicalIF":0.0,"publicationDate":"1982-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91379283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-07-01DOI: 10.1088/0032-1028/25/9/003
K. Tsuchida, S. Miyake, K. Kadota, J. Fujita
A new method based on the laser-induced fluorescence method has been developed to measure the spatial electron density distribution in plasmas. The local electron density can be determined by observing the intensity ratio of the laser- to the collision-induced fluorescence. A spatial electron density distribution of a helium plasma (Te approximately 6 eV, ne:1011-12 cm-3) has been determined by observing the He(31P to 21S) laser-induced fluorescence and the He(31D to 21P) collision-induced fluorescence resulting from the He(31P to 31D) process due to collisions with electrons. The comparison of the result with that of a conventional method proves this new method is of practical use in the space-resolved measurements of plasma electron density.
{"title":"PLASMA ELECTRON DENSITY MEASUREMENTS BY LASER- AND COLLISION-INDUCED FLUORESCENCE METHOD","authors":"K. Tsuchida, S. Miyake, K. Kadota, J. Fujita","doi":"10.1088/0032-1028/25/9/003","DOIUrl":"https://doi.org/10.1088/0032-1028/25/9/003","url":null,"abstract":"A new method based on the laser-induced fluorescence method has been developed to measure the spatial electron density distribution in plasmas. The local electron density can be determined by observing the intensity ratio of the laser- to the collision-induced fluorescence. A spatial electron density distribution of a helium plasma (Te approximately 6 eV, ne:1011-12 cm-3) has been determined by observing the He(31P to 21S) laser-induced fluorescence and the He(31D to 21P) collision-induced fluorescence resulting from the He(31P to 31D) process due to collisions with electrons. The comparison of the result with that of a conventional method proves this new method is of practical use in the space-resolved measurements of plasma electron density.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"24 1","pages":"1-27"},"PeriodicalIF":0.0,"publicationDate":"1982-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73741065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-07-01DOI: 10.1016/0375-9601(83)90024-5
S. Hashimoto, N. Yamaguchi
{"title":"Observation on Stark-Shifts of Lyman α Lines of Low-Z Ions in Laser-Produced Plasmas","authors":"S. Hashimoto, N. Yamaguchi","doi":"10.1016/0375-9601(83)90024-5","DOIUrl":"https://doi.org/10.1016/0375-9601(83)90024-5","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"17 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"1982-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88174016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A simple expression of the fast-ion-induced current in the toroidal magnetic field is obtained by use of the adjoint drift-kinetic equation for electrons. The inverse aspect ratio is assumed to be small. The lowest-order terms of this ratio are retained in the calculation. By this expression, the beam-induced current for any beam distribution is easily evaluated. When the fast ions are monoenergetic, the beam-induced current is practically computed.
{"title":"The Effect of Trapped Electrons on the Beam-Induced Current II","authors":"M. Taguchi","doi":"10.1143/JPSJ.51.1975","DOIUrl":"https://doi.org/10.1143/JPSJ.51.1975","url":null,"abstract":"A simple expression of the fast-ion-induced current in the toroidal magnetic field is obtained by use of the adjoint drift-kinetic equation for electrons. The inverse aspect ratio is assumed to be small. The lowest-order terms of this ratio are retained in the calculation. By this expression, the beam-induced current for any beam distribution is easily evaluated. When the fast ions are monoenergetic, the beam-induced current is practically computed.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"13 1","pages":"1-21"},"PeriodicalIF":0.0,"publicationDate":"1982-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80933608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The lowest‐order drift equations are given in a canonical magnetic coordinate form for time‐dependent magnetic and electric fields. The advantages of the canonical Hamiltonian form are also discussed.
给出了与时间相关的磁场和电场的最低阶漂移方程的正则磁坐标形式。讨论了正则哈密顿形式的优点。
{"title":"TIME DEPENDENT DRIFT HAMILTONIAN","authors":"A. Boozer","doi":"10.1063/1.864525","DOIUrl":"https://doi.org/10.1063/1.864525","url":null,"abstract":"The lowest‐order drift equations are given in a canonical magnetic coordinate form for time‐dependent magnetic and electric fields. The advantages of the canonical Hamiltonian form are also discussed.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"51 1","pages":"2-13"},"PeriodicalIF":0.0,"publicationDate":"1982-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74870171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cross sections for one-electron capture by highly stripped ions of Be, B and C from H 2 and Ar are measured at low energies below 10 keV. The cross sections are nearly independent of the collision energy investigated. The distinct oscillation with incident ionic charge q in the cross sections are observed.
{"title":"Cross sections for one-electron capture by highly stripped ions of Be, B and C from H_2 and Ar below 10 keV","authors":"S. Takagi, S. Ohtani, K. Kadota, J. Fujita","doi":"10.1143/JPSJ.52.3759","DOIUrl":"https://doi.org/10.1143/JPSJ.52.3759","url":null,"abstract":"Cross sections for one-electron capture by highly stripped ions of Be, B and C from H 2 and Ar are measured at low energies below 10 keV. The cross sections are nearly independent of the collision energy investigated. The distinct oscillation with incident ionic charge q in the cross sections are observed.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"20 1","pages":"1-29"},"PeriodicalIF":0.0,"publicationDate":"1982-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78168281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-03-01DOI: 10.1103/PHYSREVLETT.48.1183
Y. Amagishi, A. Tsushima, M. Inutake
Axisymmetric compressional Alfven (fast) waves, which propagate into a region of an increasing magnetic field in a cylindrical plasma, are observed to be converted into ion-cyclotron (slow) waves via ion-cyclotron resonances.
{"title":"CONVERSION OF COMPRESSIONAL ALFVEN WAVES INTO ION CYCLOTRON WAVES IN INHOMOGENEOUS MAGNETIC FIELDS","authors":"Y. Amagishi, A. Tsushima, M. Inutake","doi":"10.1103/PHYSREVLETT.48.1183","DOIUrl":"https://doi.org/10.1103/PHYSREVLETT.48.1183","url":null,"abstract":"Axisymmetric compressional Alfven (fast) waves, which propagate into a region of an increasing magnetic field in a cylindrical plasma, are observed to be converted into ion-cyclotron (slow) waves via ion-cyclotron resonances.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"9 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"1982-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73887836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1981-12-28DOI: 10.1103/PHYSREVLETT.47.1899
H. Sugai
An extraordinary wave is normally incident on a large volume magnetoplasma, then below the second gyroharmonic, conversion into short-wavelength Bernstein waves is observed near the upper-hybrid layer. Significant conversion efficiency is attained in the optimum conditions. In the high power incidence, considerable electron heating due to the converted wave is found to be localized in the mode-conversion region.
{"title":"Mode Conversion and Local Heating below the Second Electron Cyclotron Harmonic","authors":"H. Sugai","doi":"10.1103/PHYSREVLETT.47.1899","DOIUrl":"https://doi.org/10.1103/PHYSREVLETT.47.1899","url":null,"abstract":"An extraordinary wave is normally incident on a large volume magnetoplasma, then below the second gyroharmonic, conversion into short-wavelength Bernstein waves is observed near the upper-hybrid layer. Significant conversion efficiency is attained in the optimum conditions. In the high power incidence, considerable electron heating due to the converted wave is found to be localized in the mode-conversion region.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"13 1","pages":"2-13"},"PeriodicalIF":0.0,"publicationDate":"1981-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90079065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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