In order to interpret the spectral-line intensities emitted from various plasmas, a collisional-radiative-model program has been constructed for heliumlike ions. In this model a population of 61 excited levels is considered, and excitation, deexcitation, ionization and three-body recombination by electron collisions, spontaneous transition, radiative recombination, and dielectronic recombination have been included. For these processes, the most reliable rate coefficients, experimental or theoretical, have been employed. A detailed account is given of the program along with the review of the rate coefficients adopted. As an example of its applications, line-intensity data for theta-pinch plasmas are analyzed; for oxygen the three sets of experiments are consistent with the present calculation. For the case of carbon, however, the intensity ratio cannot be interpreted consistently on the assumption of the ionizing-plasma model. Rather, it is strongly suggested that the plasma has a significant contribution from the recombining-plasma component.
{"title":"Collisional-Radiative Model for Helium-Like Ions : Application to Intermediate-Density Plasmas","authors":"T. Fujimoto, T. Kato","doi":"10.1103/PHYSREVA.30.379","DOIUrl":"https://doi.org/10.1103/PHYSREVA.30.379","url":null,"abstract":"In order to interpret the spectral-line intensities emitted from various plasmas, a collisional-radiative-model program has been constructed for heliumlike ions. In this model a population of 61 excited levels is considered, and excitation, deexcitation, ionization and three-body recombination by electron collisions, spontaneous transition, radiative recombination, and dielectronic recombination have been included. For these processes, the most reliable rate coefficients, experimental or theoretical, have been employed. A detailed account is given of the program along with the review of the rate coefficients adopted. As an example of its applications, line-intensity data for theta-pinch plasmas are analyzed; for oxygen the three sets of experiments are consistent with the present calculation. For the case of carbon, however, the intensity ratio cannot be interpreted consistently on the assumption of the ionizing-plasma model. Rather, it is strongly suggested that the plasma has a significant contribution from the recombining-plasma component.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"31 1","pages":"1-38"},"PeriodicalIF":0.0,"publicationDate":"1983-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88851624","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 : 1983-08-01DOI: 10.1017/S0263034600000586
H. Murakami, T. Aoki, S. Kawata, K. Niu
Rotating motions of propagating LIB are analyzed in order to suppress the instability of mixed mode of the Kelvin-Helmholtz, tearing and sausage types by the action of a self-induced magnetic field in the axial direction. The beams are assumed to be charge-neutralized but not current-neutralized. The steady-state solutions of propagating LIB with rotations are numerically obtained first. Through the dispersion relation with respect to the ikonal type of perturbations which are added to the steady-state solutions, the growth rates of instabilities appearing in LIB are obtained. It is concluded that if the mean rotating velocity of LIB is comparable to the propagation velocity, in other words, if the induced magnetic field intensity in the axial direction is comparable to the magnetic field intensity in the azimuthal direction, the macro-instability disappears in the propagating ion beam.
{"title":"Rotating and Propagating LIB Stabilized by Self-Induced Magnetic Field","authors":"H. Murakami, T. Aoki, S. Kawata, K. Niu","doi":"10.1017/S0263034600000586","DOIUrl":"https://doi.org/10.1017/S0263034600000586","url":null,"abstract":"Rotating motions of propagating LIB are analyzed in order to suppress the instability of mixed mode of the Kelvin-Helmholtz, tearing and sausage types by the action of a self-induced magnetic field in the axial direction. The beams are assumed to be charge-neutralized but not current-neutralized. The steady-state solutions of propagating LIB with rotations are numerically obtained first. Through the dispersion relation with respect to the ikonal type of perturbations which are added to the steady-state solutions, the growth rates of instabilities appearing in LIB are obtained. It is concluded that if the mean rotating velocity of LIB is comparable to the propagation velocity, in other words, if the induced magnetic field intensity in the axial direction is comparable to the magnetic field intensity in the azimuthal direction, the macro-instability disappears in the propagating ion beam.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"5 1","pages":"1-27"},"PeriodicalIF":0.0,"publicationDate":"1983-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79206719","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 reduced set of ideal magnetohydrodynamic equations is derived for large‐aspect‐ratio, low‐β tokamaks that adequately describes the linear and nonlinear evolution of ideal internal kink modes in tokamaks.
{"title":"REDUCED EQUATIONS FOR INTERNAL KINKS IN TOKAMAKS","authors":"R. Izzo, W. Park, J. Manickam, J. DeLucia","doi":"10.1063/1.864030","DOIUrl":"https://doi.org/10.1063/1.864030","url":null,"abstract":"A reduced set of ideal magnetohydrodynamic equations is derived for large‐aspect‐ratio, low‐β tokamaks that adequately describes the linear and nonlinear evolution of ideal internal kink modes in tokamaks.","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"35 1","pages":"30-42"},"PeriodicalIF":0.0,"publicationDate":"1983-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88500188","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":"The Effect of Trapped Electrons on the Wave-Induced Current","authors":"M. Taguchi","doi":"10.1143/jpsj.52.2035","DOIUrl":"https://doi.org/10.1143/jpsj.52.2035","url":null,"abstract":"","PeriodicalId":22276,"journal":{"name":"The annual research report","volume":"7 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"1983-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73362170","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}
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}
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