Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027662
D. Ćirić, T. Jones, D. Edwards, D. Martin, A. Bickley, D.P. Brown, S. Cox, A. Dines, J. Dobbing, J. Milnes, S. R. Shaw, D. Stork, E. Surrey, M. Watson, D. Young, I. Young, P. Bayetti, J. Doncel
The programme of the JET Octant 8 Neutral Injector Box (NIB) upgrade is the first, and to date the largest, modification of the JET machine approved within the current EFDA-JET framework. When completed in autumn 2002, this programme will result in the total injected deuterium neutral beam power of /spl sim/28 MW, compared to the present maximum level of /spl sim/20.5 MW. This paper gives an overview of various engineering activities and experimental trials carried out in support of this ongoing upgrade programme.
{"title":"Upgrade of the JET neutral beam heating system","authors":"D. Ćirić, T. Jones, D. Edwards, D. Martin, A. Bickley, D.P. Brown, S. Cox, A. Dines, J. Dobbing, J. Milnes, S. R. Shaw, D. Stork, E. Surrey, M. Watson, D. Young, I. Young, P. Bayetti, J. Doncel","doi":"10.1109/FUSION.2002.1027662","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027662","url":null,"abstract":"The programme of the JET Octant 8 Neutral Injector Box (NIB) upgrade is the first, and to date the largest, modification of the JET machine approved within the current EFDA-JET framework. When completed in autumn 2002, this programme will result in the total injected deuterium neutral beam power of /spl sim/28 MW, compared to the present maximum level of /spl sim/20.5 MW. This paper gives an overview of various engineering activities and experimental trials carried out in support of this ongoing upgrade programme.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"16 1","pages":"140-143"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75016258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027701
G. Federici, V. Barabash, G. Janeschitz, R. Tivey, A. Loarte, J. Roth, C. Skinner, W. Wampler
Designing a robust interface between a thermonuclear plasma and the solid material environment remains a major challenge for next-step fusion devices and future power fusion reactors. Challenging trade-offs in material choice for plasma-facing components were identified in the internationally co-ordinated R&D program supporting the Engineering Design Activities of the ITER project. This paper surveys factors relevant to material choices in next-step devices, describes advantages and disadvantages of the various options, and discusses how their application depends on the specific operational requirements. Advances in materials technology with high-Z materials, together with improved plasma control leading to reduction and mitigation of off-normal events such as disruptions and ELMs, are an essential part of the long-term solution.
{"title":"Selection of plasma-facing materials in next-step fusion devices","authors":"G. Federici, V. Barabash, G. Janeschitz, R. Tivey, A. Loarte, J. Roth, C. Skinner, W. Wampler","doi":"10.1109/FUSION.2002.1027701","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027701","url":null,"abstract":"Designing a robust interface between a thermonuclear plasma and the solid material environment remains a major challenge for next-step fusion devices and future power fusion reactors. Challenging trade-offs in material choice for plasma-facing components were identified in the internationally co-ordinated R&D program supporting the Engineering Design Activities of the ITER project. This paper surveys factors relevant to material choices in next-step devices, describes advantages and disadvantages of the various options, and discusses how their application depends on the specific operational requirements. Advances in materials technology with high-Z materials, together with improved plasma control leading to reduction and mitigation of off-normal events such as disruptions and ELMs, are an essential part of the long-term solution.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"37 1","pages":"311-320"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75191706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027732
A. Kellman
Significant progress has been made in a number of key scientific and engineering areas that are critical to advanced tokamak operation on the DIII-D tokamak. Improved error field correction coupled with plasma rotation has resulted in a passive wall stabilized discharge at twice the no-wall beta limit. Active feedback stabilization of the resistive wall mode (RWM) has been improved using newly installed internal magnetic sensors and external control coils. A set of internal control coils for RWM feedback has been designed that should permit operation at close to the ideal limit. Real-time stabilization of the neoclassical tearing mode has been achieved using a new "search and suppress" control algorithm coupled with electron cyclotron current drive (ECCD). The ECCD system is routinely providing in excess of 2 MW of power for 2 s pulses. Modeling predicts that measured efficiencies of ECCD are consistent with future, fully non-inductive AT target discharges. Massive injection of Ar gas has resulted in successful mitigation of disruptions in high performance discharges without producing high energy runaway electrons. Finally, an upgraded digital plasma control system will provide significantly more capability to provide real time measurement and control of plasma profiles and instabilities.
{"title":"Recent progress from the DIII-D program","authors":"A. Kellman","doi":"10.1109/FUSION.2002.1027732","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027732","url":null,"abstract":"Significant progress has been made in a number of key scientific and engineering areas that are critical to advanced tokamak operation on the DIII-D tokamak. Improved error field correction coupled with plasma rotation has resulted in a passive wall stabilized discharge at twice the no-wall beta limit. Active feedback stabilization of the resistive wall mode (RWM) has been improved using newly installed internal magnetic sensors and external control coils. A set of internal control coils for RWM feedback has been designed that should permit operation at close to the ideal limit. Real-time stabilization of the neoclassical tearing mode has been achieved using a new \"search and suppress\" control algorithm coupled with electron cyclotron current drive (ECCD). The ECCD system is routinely providing in excess of 2 MW of power for 2 s pulses. Modeling predicts that measured efficiencies of ECCD are consistent with future, fully non-inductive AT target discharges. Massive injection of Ar gas has resulted in successful mitigation of disruptions in high performance discharges without producing high energy runaway electrons. Finally, an upgraded digital plasma control system will provide significantly more capability to provide real time measurement and control of plasma profiles and instabilities.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"85 1","pages":"442-447"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79355925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027713
D. Youchison, R. Nygren, J. S. O'Dell, J. M. McDonald, T. Lutz
High-Z armor is appropriate for use on plasma facing components (pfcs) subjected to very high heat loads and low plasma edge temperatures. During the past several years much progress was made on the development of tungsten rod armor bonded to water-cooled heatsinks. These pfcs can endure heat fluxes near 25 MW/m/sup 2/ typical of high density burning plasmas without thermal stress cracking, melting or debonding of the armor. Tungsten rod armor is considered for use on portions of the ITER-FEAT divertor and is the reference design for the FIRE divertor. This year, three 40-cm-long, dual-channel, water-cooled, tungsten rod-armored pfc mock-ups were fabricated by Plasma Processes, Inc. and tested at the Plasma Materials Test Facility at Sandia National Laboratories. The 32-mm-wide armor was fabricated by plasma spraying copper onto the back of a hexagonal close-packed array of 3-mm-diameter tungsten welding rods with an exposed height of 10-mm. In one of the mock-ups, designated PW-8, the armor was joined to a copper heat sink by hot isostatic pressing using a Ni interlayer. In another type of mock-up, designated PW-14, full-penetration electron beam welding was used to join the tungsten and plasma-sprayed copper substrate to the heatsink. The mock-ups were tested with 4 MPa, 20/spl deg/C water at 15 m/s using a rastered electron beam system. The highest absorbed heat flux, 24 MW/m/sup 2/ over a 10-cm heated length, brought the rod ends to the melting point. Fabrication issues, thermal fatigue performance at 20 MW/m, and the results of surface analyses of the rods also are reported. These test results help qualify the pfc design for use in the FIRE divertor.
{"title":"Advances in tungsten-armored plasma facing components","authors":"D. Youchison, R. Nygren, J. S. O'Dell, J. M. McDonald, T. Lutz","doi":"10.1109/FUSION.2002.1027713","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027713","url":null,"abstract":"High-Z armor is appropriate for use on plasma facing components (pfcs) subjected to very high heat loads and low plasma edge temperatures. During the past several years much progress was made on the development of tungsten rod armor bonded to water-cooled heatsinks. These pfcs can endure heat fluxes near 25 MW/m/sup 2/ typical of high density burning plasmas without thermal stress cracking, melting or debonding of the armor. Tungsten rod armor is considered for use on portions of the ITER-FEAT divertor and is the reference design for the FIRE divertor. This year, three 40-cm-long, dual-channel, water-cooled, tungsten rod-armored pfc mock-ups were fabricated by Plasma Processes, Inc. and tested at the Plasma Materials Test Facility at Sandia National Laboratories. The 32-mm-wide armor was fabricated by plasma spraying copper onto the back of a hexagonal close-packed array of 3-mm-diameter tungsten welding rods with an exposed height of 10-mm. In one of the mock-ups, designated PW-8, the armor was joined to a copper heat sink by hot isostatic pressing using a Ni interlayer. In another type of mock-up, designated PW-14, full-penetration electron beam welding was used to join the tungsten and plasma-sprayed copper substrate to the heatsink. The mock-ups were tested with 4 MPa, 20/spl deg/C water at 15 m/s using a rastered electron beam system. The highest absorbed heat flux, 24 MW/m/sup 2/ over a 10-cm heated length, brought the rod ends to the melting point. Fabrication issues, thermal fatigue performance at 20 MW/m, and the results of surface analyses of the rods also are reported. These test results help qualify the pfc design for use in the FIRE divertor.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"330 1","pages":"364-367"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80479645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027734
A. Sykes, J. Ahn, R. Akers, E. Arends, K. Axon, R. Buttery, C. Byrom, P. Carolan, D. Ćirić, N. Conway, M. Cox, G. Counsell, G. Cunningham, A. Darke, J. Dowling, M. Dunstan, A. Field, S. Fielding, S. Gee, M. Gryaznevich, R. Hayward, P. Helander, M. Hood, A. Kirk, I. Lehane, B. Lloyd, G. Maddison, S. J. Manhood, R. Martín, G. McArdle, H. Meyer, M. Mgrath, A. Morris, M. Nightingale, T. Pinfold, M. Price, C. Ribeiro, D. Robinson, V. Shevchenko, K. Stammers, A. Tabasso, D. Taylor, M. Tournianski, M. Valovič, G. Voss, M. Walsh, S. Warder, H. Wilson
The MAST (Mega-Amp Spherical Tokamak) experiment has been operational since Jan 2000. Results from MAST are important both in evaluating the potential of future ST fusion devices, and in developing understanding of processes relevant to conventional aspect ratio tokamaks. In this paper methods of initiating, ramping up, and sustaining the high plasma currents associated with ST fusion devices are discussed. New physics results, including the effectiveness of inboard gas puffing, the threshold power required for the L-H transition, and the 'natural' divertor configuration are given. Plans for improvements during 2002 are outlined.
{"title":"Results from the MAST spherical tokamak","authors":"A. Sykes, J. Ahn, R. Akers, E. Arends, K. Axon, R. Buttery, C. Byrom, P. Carolan, D. Ćirić, N. Conway, M. Cox, G. Counsell, G. Cunningham, A. Darke, J. Dowling, M. Dunstan, A. Field, S. Fielding, S. Gee, M. Gryaznevich, R. Hayward, P. Helander, M. Hood, A. Kirk, I. Lehane, B. Lloyd, G. Maddison, S. J. Manhood, R. Martín, G. McArdle, H. Meyer, M. Mgrath, A. Morris, M. Nightingale, T. Pinfold, M. Price, C. Ribeiro, D. Robinson, V. Shevchenko, K. Stammers, A. Tabasso, D. Taylor, M. Tournianski, M. Valovič, G. Voss, M. Walsh, S. Warder, H. Wilson","doi":"10.1109/FUSION.2002.1027734","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027734","url":null,"abstract":"The MAST (Mega-Amp Spherical Tokamak) experiment has been operational since Jan 2000. Results from MAST are important both in evaluating the potential of future ST fusion devices, and in developing understanding of processes relevant to conventional aspect ratio tokamaks. In this paper methods of initiating, ramping up, and sustaining the high plasma currents associated with ST fusion devices are discussed. New physics results, including the effectiveness of inboard gas puffing, the threshold power required for the L-H transition, and the 'natural' divertor configuration are given. Plans for improvements during 2002 are outlined.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"37 1","pages":"454-460"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85316453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027739
S. Zinkle, A. Kohyama
An overview is given regarding recent work on the development of advanced structural and nonstructural materials for fusion reactors. In particular, research highlights are presented on advanced ferritic/martensitic steels, V alloys, Mo alloys, and SiC composites, which are candidate structural materials for fusion systems. The potential for developing improved high-strength, high-conductivity Cu alloys for normal conducting magnets and divertor structures is assessed. The current status of several key nonstructural materials systems (including insulators and optical materials) is also summarized.
{"title":"Advanced materials for fusion energy","authors":"S. Zinkle, A. Kohyama","doi":"10.1109/FUSION.2002.1027739","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027739","url":null,"abstract":"An overview is given regarding recent work on the development of advanced structural and nonstructural materials for fusion reactors. In particular, research highlights are presented on advanced ferritic/martensitic steels, V alloys, Mo alloys, and SiC composites, which are candidate structural materials for fusion systems. The potential for developing improved high-strength, high-conductivity Cu alloys for normal conducting magnets and divertor structures is assessed. The current status of several key nonstructural materials systems (including insulators and optical materials) is also summarized.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"6 1","pages":"477-483"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84444979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027716
Yuntao Song, D. Yao, Songtao Wu, Jie Yu, P. Weng, Yihua Liu, Jionghua Wang, X. Wu
Vacuum vessel of the HT-7U is a fully welded toroidal structure with noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outboard mid-plane and thirty-two vertical ports on the top and bottom are designed for diagnostics, plasma heating, current driving, vacuum pumping and gas puffing. Bellows on these ports are used for flexible components to absorb the relative displacement in radial and vertical directions due to the external load, thermal expansion or contraction, assembly toleration and as well as for isolation of mechanical vibration. Some three-dimension finite element COSMOS models were performed to analysis its structural strength, stiffness and fatigue life, laying the emphasis on these bellows static stress analysis. The load case spectra during vacuum vessel operation were also simulated on a model from the view of fatigue design. It was confirmed that these bellows have sufficient strength in range of the design load conditions. The results showed the bellows peak stress was 87 MPa and its fatigue cumulative usage factor was only 0.01, which was less than critical value of 1. Now all kinds of bellows have been designed. In order to accumulate some engineering experiences and probe into some molding die and welding technologies, a prototypical bellows have been fabricated. At the same time a mechanical testing apparatus was designed for proof tests on the prototypical bellows to verify its functional and structure capability. The experimental data indicated that the results of finite element analysis were coincident with experimental test results. It has been proved that the present vacuum vessel's bellows are reasonable and feasible.
{"title":"Structure analysis and experiment research of the welded bellows for the ports of the HT-7U vacuum vessel","authors":"Yuntao Song, D. Yao, Songtao Wu, Jie Yu, P. Weng, Yihua Liu, Jionghua Wang, X. Wu","doi":"10.1109/FUSION.2002.1027716","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027716","url":null,"abstract":"Vacuum vessel of the HT-7U is a fully welded toroidal structure with noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outboard mid-plane and thirty-two vertical ports on the top and bottom are designed for diagnostics, plasma heating, current driving, vacuum pumping and gas puffing. Bellows on these ports are used for flexible components to absorb the relative displacement in radial and vertical directions due to the external load, thermal expansion or contraction, assembly toleration and as well as for isolation of mechanical vibration. Some three-dimension finite element COSMOS models were performed to analysis its structural strength, stiffness and fatigue life, laying the emphasis on these bellows static stress analysis. The load case spectra during vacuum vessel operation were also simulated on a model from the view of fatigue design. It was confirmed that these bellows have sufficient strength in range of the design load conditions. The results showed the bellows peak stress was 87 MPa and its fatigue cumulative usage factor was only 0.01, which was less than critical value of 1. Now all kinds of bellows have been designed. In order to accumulate some engineering experiences and probe into some molding die and welding technologies, a prototypical bellows have been fabricated. At the same time a mechanical testing apparatus was designed for proof tests on the prototypical bellows to verify its functional and structure capability. The experimental data indicated that the results of finite element analysis were coincident with experimental test results. It has been proved that the present vacuum vessel's bellows are reasonable and feasible.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"8 1","pages":"376-379"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84156182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027648
M. Kushwah, B. Pal, Y. Srinivas, K. Sathyanarayana, P. Khilar, P. Shah, S. Kulkarni, A. Makwana, B. Kadia, K. Parmar, S. Dani, R. Singh, K. Parmar, D. Bora
Initial testing and commissioning of two high power klystrons (TH2103D) and gyrotron (VGA8000A19) have been carried out at our Institute. Each of the klystrons is capable of delivering 500 kW at 3.7 GHz, to be used for non-inductive lower hybrid current drive (LHCD) in the Steady State Superconducting Tokamak (SST-1). The gyrotron is capable of delivering 200 KW at 28 GHz, for breakdown and electron cyclotron resonant heating (ECRH) experiments on Aditya tokamak. The potential appearing at the anode point with respect to the cathode will turn-ON, turn-OFF and control the beam current. Thus these anode modulator power supplies control the out put power of the devices. Main input for both the power supplies is derived from the cathode power supply. A -2 kV bias power supply is connected between the modulator output and anode terminal to suppress dark current. The output pulse duration is adjustable from 50 msec. to 1000 sec. by the control system. The oil cooled tetrode YU155 is used as shunt voltage regulator in the klystron anode modulator power supply. A potential divider is made with the tetrode as a series element. It operates in its linear range and a variable voltage is available at the klystron anode by varying the impedance of the tetrode.
{"title":"Anode modulator power supplies for continuous duty 500 kW klystrons (TH2103D) & 200 kW gyrotron (VGA8000A19)","authors":"M. Kushwah, B. Pal, Y. Srinivas, K. Sathyanarayana, P. Khilar, P. Shah, S. Kulkarni, A. Makwana, B. Kadia, K. Parmar, S. Dani, R. Singh, K. Parmar, D. Bora","doi":"10.1109/FUSION.2002.1027648","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027648","url":null,"abstract":"Initial testing and commissioning of two high power klystrons (TH2103D) and gyrotron (VGA8000A19) have been carried out at our Institute. Each of the klystrons is capable of delivering 500 kW at 3.7 GHz, to be used for non-inductive lower hybrid current drive (LHCD) in the Steady State Superconducting Tokamak (SST-1). The gyrotron is capable of delivering 200 KW at 28 GHz, for breakdown and electron cyclotron resonant heating (ECRH) experiments on Aditya tokamak. The potential appearing at the anode point with respect to the cathode will turn-ON, turn-OFF and control the beam current. Thus these anode modulator power supplies control the out put power of the devices. Main input for both the power supplies is derived from the cathode power supply. A -2 kV bias power supply is connected between the modulator output and anode terminal to suppress dark current. The output pulse duration is adjustable from 50 msec. to 1000 sec. by the control system. The oil cooled tetrode YU155 is used as shunt voltage regulator in the klystron anode modulator power supply. A potential divider is made with the tetrode as a series element. It operates in its linear range and a variable voltage is available at the klystron anode by varying the impedance of the tetrode.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"40 1","pages":"84-87"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87844996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027651
C. Brunkhorst
High power RF systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance.
{"title":"Models for automated tube performance calculations","authors":"C. Brunkhorst","doi":"10.1109/FUSION.2002.1027651","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027651","url":null,"abstract":"High power RF systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"117 1","pages":"95-98"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86800278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-11-07DOI: 10.1109/FUSION.2002.1027719
J. Yagyu, T. Arai, A. Kaminaga, K. Kizu, M. Arai, N. Miya
In JT-60U, boronization using hydride-decaborane (B/sub 10/H/sub 14/) vaporization has been conducted for the first wall conditioning. Compared to other discharge cleaning, boronization is claimed to be efficient in reduction of both oxygen impurities and hydrogen recycling in plasma. However, there are a few issues for reducing of hydrogen included in boron film and for stabilizing of DC glow discharge cleaning (GDC) during the boronization. To solve the issues, a new boronization method using deuterated-decaborane (B/sub 10/D/sub 14/) was adopted instead of the conventional B/sub 10/H/sub 14/. As a result, hydrogen content in the boron film decreased clearly, and the discharge conditioning shots for decreasing hydrogen concentration in plasmas after the boronization was reduced to 1/10 in comparison to the conventional process. Furthermore, GDC became stable, with only helium dilution gas, and it was possible to save 30 hours in maximum of the time necessary for boronization. It was found that the boronization using B/sub 10/D/sub 14/ is very efficient and effective method for the first wall conditioning.
{"title":"Boronization using deuterated-decaborane in JT-60U","authors":"J. Yagyu, T. Arai, A. Kaminaga, K. Kizu, M. Arai, N. Miya","doi":"10.1109/FUSION.2002.1027719","DOIUrl":"https://doi.org/10.1109/FUSION.2002.1027719","url":null,"abstract":"In JT-60U, boronization using hydride-decaborane (B/sub 10/H/sub 14/) vaporization has been conducted for the first wall conditioning. Compared to other discharge cleaning, boronization is claimed to be efficient in reduction of both oxygen impurities and hydrogen recycling in plasma. However, there are a few issues for reducing of hydrogen included in boron film and for stabilizing of DC glow discharge cleaning (GDC) during the boronization. To solve the issues, a new boronization method using deuterated-decaborane (B/sub 10/D/sub 14/) was adopted instead of the conventional B/sub 10/H/sub 14/. As a result, hydrogen content in the boron film decreased clearly, and the discharge conditioning shots for decreasing hydrogen concentration in plasmas after the boronization was reduced to 1/10 in comparison to the conventional process. Furthermore, GDC became stable, with only helium dilution gas, and it was possible to save 30 hours in maximum of the time necessary for boronization. It was found that the boronization using B/sub 10/D/sub 14/ is very efficient and effective method for the first wall conditioning.","PeriodicalId":44192,"journal":{"name":"NINETEENTH CENTURY MUSIC","volume":"37 1","pages":"388-391"},"PeriodicalIF":0.4,"publicationDate":"2002-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74769705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"艺术学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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