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RF Systems for a Proposed Next Step Option (FIRE)

Description: FIRE (Fusion Ignition Research Experiment) is a high-field, burning-plasma tokamak that is being studied as a possible option for future fusion research. Preliminary parameters for this machine are R<sub>0</sub> approximately equal to 2 m, a approximately equal to 0.5 m, B<sub>0</sub> approximately equal to 10 T, and I<sub>p</sub> approximately equal to 6 MA. Magnetic field coils are to be made of copper and precooled with LN<sub>2</sub> before each shot. The flat-top pulse length desired is gr… more
Date: April 12, 1999
Creator: Carter, M. D. & Swain, D. W.
Partner: UNT Libraries Government Documents Department
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On the Nature of Monster Sawteeth during ICRF Heating

Description: A correlation between the presence of Energetic Particle Modes and long period sawteeth is explored. The crash of monster sawteeth is explained in terms of the loss of the stabilizing fast particles due to the EPM. High qa discharges, which never develop long period sawteeth, are explained in terms of ion loss due to Toroidal Alfvén Eigenmodes (TAE).
Date: May 1, 1999
Creator: Phillips, C. K.; Fredrickson, E. D.; Schilling, G.; Hosea, J. C.; Wilson, J. R.; Gorelenkov, N. N. et al.
Partner: UNT Libraries Government Documents Department
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Wave generation and heating near ion cyclotron frequency in the ST Tokamak

Description: The results of the recent, high power ICRH experiments performed on the ST Tokamak are reported. It was demonstrated that both the fast and slow waves could be generated in toroidal geometry, and heating of the plasma ions at power levels up to 1 MW was observed both at the ion cyclotron frequency ($omega$/sub ci/) and its second harmonic (2$omega$/sub ci/). Measurements by a charge exchange neutral detector directed tangentially to the plasma torus revealed that at 2$omega$/sub ci/ the ion ene… more
Date: October 1, 1975
Creator: Takahashi, H.
Partner: UNT Libraries Government Documents Department
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Design of RF Systems for the RTD Mission VASIMR

Description: The first flight test of the variable specific impulse magnetoplasma rocket (VASIMR) is tentatively scheduled for the Radiation and Technology Demonstration (RTD) in 2003. This mission to map the radiation environment out to several earth radii will employ both a Hall thruster and a VASIMR during its six months duration, beginning from low earth orbit. The mission will be powered by a solar array providing 12 kW of direct current electricity at 50 V. The VASIMR utilizes radiofrequency (RF) powe… more
Date: April 12, 1999
Creator: Baity, F. W.; Barber, G. C.; Carter, M. D.; Chang-Diaz, F. R.; Goulding, R. H.; McCaskill, G. E. et al.
Partner: UNT Libraries Government Documents Department
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Design of the ICRH antenna for TPX

Description: A 6-MW ion cyclotron (IC) system for the Tokamak Physics Experiment (TPX) is in the preliminary design phase. In conjunction with the 3-MW Lower Hybrid system and the 8-MW neutral beam system, the IC system will provide heating and current-drive capabilities to explore advanced tokamak physics and long-pulse (1000 s) operation. The IC launcher consists of six nickel-plated current straps arranged toroidally in pairs behind three water-cooled Faraday shields. The Faraday shields can be independe… more
Date: January 1, 1996
Creator: Fogelman, C. H.; Goranson, P. L.; Swain, D. W.; Ryan, P. M. & Yugo, J. J.
Partner: UNT Libraries Government Documents Department
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ICRF heating of deuterium-tritium plasmas in TFTR

Description: The first experiments to heat D-T plasmas in the ion cyclotron range of frequencies (ICRF) have been performed on the Tokamak Fusion Test Reactor (TFTR). These experiments have two major objectives: to study the RF physics of ICRF-heated D-T plasmas and to enhance the performance of D-T discharges. Experiments have been conducted at 43 MHz with out-of-phase current strap excitation to explore n{sub T}/n{sub e} concentrations up to approximately 40%. In these experiments n{sub T}/n{sub e} was li… more
Date: March 1, 1995
Creator: Taylor, G.; Murakami, M. & Adler, H.
Partner: UNT Libraries Government Documents Department
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Lithium pellet injection experiments on the Alcator C-Mod tokamak

Description: A pellet enhanced performance mode, showing significantly reduced core transport, is regularly obtained after the injection of deeply penetrating lithium pellets into Alcator C-Mod discharges. These transient modes, which typically persist about two energy confinement times, are characterized by a steep pressure gradient ({ell}{sub p} {le} a/5) in the inner third of the plasma, indicating the presence of an internal transport barrier. Inside this barrier, particle and energy diffusivities are g… more
Date: June 1, 1996
Creator: Garnier, D.T.
Partner: UNT Libraries Government Documents Department
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ICRF heating and current drive experiments on TFTR

Description: Recent experiments in the Ion Cyclotron Range of Frequencies (ICRF) at TFTR have focused on the RF physics relevant to advanced tokamak D-T reactors. Experiments performed either tested confinement in reactor relevant plasmas or tested specific ICRF heating scenarios under consideration for reactors. H-minority heating was used to supply identical heating sources for matched D-T and D only L-mode plasmas to determine the species scaling for energy confinement. Second harmonic tritium heating wa… more
Date: December 31, 1996
Creator: Rogers, J. H.; Hosea, J. C. & Phillips, C. K.
Partner: UNT Libraries Government Documents Department
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Electrical optimization of the ICH antenna array for ITER

Description: The present design of the ITER ICH antenna array comprises two poloidal by four toroidal current elements in each of four ports.Each current element forms a resonant double loop (RDL) with power fed to a pretuned matchpoint on the strap; the matching is accomplished using slow-wave transmission lines as adjustable shorted-stub tuners on either end of the current strap. The power requirement is 12.5 MW per port over the frequency range of 40--70 MHz, with extended operation to 80 MHz desirable. … more
Date: August 1, 1997
Creator: Ryan, P. M.; Swain, D. W.; Carter, M. D.; Taylor, D. J. & Bosia, G.
Partner: UNT Libraries Government Documents Department
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Engineering design of the ITER RF systems

Description: Parallel conceptual design efforts for auxiliary heating systems on ITER are being carried out in both the electron cyclotron range of frequencies (ECRF) and ion cyclotron range of frequencies (ICRF). These systems are required to deliver a minimum of 50 MW of CW power to the plasma for the primary purpose of heating and the secondary purpose of current drive. Current designs of the two systems are presented and the primary design issues are discussed.
Date: December 31, 1994
Creator: Makowski, M.; Bosia, G.; Nagashima, T. & Remsen, D.
Partner: UNT Libraries Government Documents Department
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The technology of ICRF systems

Description: The technology of ICRF systems has made substantial gains in the past few years. The total power levels have increased from the 5-MW level to greater than 20 MW; the pulse lengths have increased from the 100-msec level to 30 seconds. Recently, fast wave current drive (FWCD) has been demonstrated using phased arrays of ICRF antennas. In order to achieve such large gains, substantial changes and improvements were needed in the level of design analysis, fabrication techniques, and system controls.
Date: December 1995
Creator: Baity, F. W.; Barber, G. C. & Bigelow, T. S.
Partner: UNT Libraries Government Documents Department
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Development of fast wave systems tolerant of time-varying loading

Description: A new approach to fast wave antenna array design based on the traveling wave antenna has been successfully demonstrated on the JFT-2M tokamak. A traveling wave antenna is powered though a single feed and the power flow from element to element is only via mutual reactive coupling. A combine is a particular type of traveling wave antenna, in which only the fed element and the element at the downstream end of the array are connected to vacuum feed troughs, while the intermediate elements are termi… more
Date: June 1, 1996
Creator: Pinsker, R. I.; Moeller, C. P.; Petty, C. C. & Phelps, D. A.
Partner: UNT Libraries Government Documents Department
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ICRF heating on helical devices

Description: Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Results… more
Date: September 1, 1995
Creator: Rasmussen, D.A.; Lyon, J.F. & Hoffman, D.J.
Partner: UNT Libraries Government Documents Department
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ICRF heating on helical devices

Description: Ion cyclotron range of frequency (ICRF) heating is currently in use on CHS and W7-AS and is a major element of the heating planned for steady state helical devices. In helical devices, the lack of a toroidal current eliminates both disruptions and the need for ICRF current drive, simplifying the design of antenna structures as compared to tokamak applications. However the survivability of plasma facing components and steady state cooling issues are directly applicable to tokamak devices. Result… more
Date: September 1, 1995
Creator: Rasmussen, D. A.; Lyon, J. F.; Hoffman, D. J.; Murakami, M.; England, A. C.; Wilgen, J. B. et al.
Partner: UNT Libraries Government Documents Department
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Design options for an ITER ion cyclotron system

Description: Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented.
Date: September 1, 1995
Creator: Swain, D. W.; Baity, F. W.; Bigelow, T. S.; Ryan, P. M.; Goulding, R. H.; Carter, M. D. et al.
Partner: UNT Libraries Government Documents Department
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Design of fast tuning elements for the ITER ICH system

Description: The coupling between the ion cyclotron (IC) antenna and the ITER plasma (as expressed by the load resistance the antenna sees) will experience relatively fast variations due to plasma edge profile modifications. If uncompensated, these will cause an increase in the amount of power reflected back to the transmitter and ultimately a decrease in the amount of radio frequency (rf) power to the plasma caused by protective suppression of the amount of rf power generated by the transmitter. The goals … more
Date: May 1, 1996
Creator: Swain, D. W. & Goulding, R. H.
Partner: UNT Libraries Government Documents Department
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Commissioning of the long-pulse fast wave current drive antennas for DIII-D

Description: Two new four-element fast wave current drive antennas have been installed on DIII-D. These antennas are designed for 10-s pulses at 2 MW each in the frequency range of 30 to 120 MHz. Each element comprises two poloidal segments fed in parallel in order to optimize plasma coupling at the upper end of the frequency range. The antennas are mounted on opposite sides of the vacuum vessel, in ports designated 0{degrees} and 180{degrees} after their toroidal angle. Each antenna array is fed by a singl… more
Date: September 1, 1995
Creator: Baity, F. W.; Barber, G. C.; Goulding, R. H.; Hoffman, D. J.; DeGrassie, J. S.; Pinsker, R. I. et al.
Partner: UNT Libraries Government Documents Department
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Progress on radio frequency auxiliary heating system designs in ITER

Description: ITER will require over 100 MW of auxiliary power for heating, on- and off-axis current drive, accessing the H-mode, and plasma shut-down. The Electron Cyclotron Range of Frequencies (ECRF) and Ion Cyclotron Range of Frequencies (ICRF) are two forms of Radio Frequency (RF) auxiliary power being developed for these applications. Design concepts for both the ECRF and ICRF systems are presented, key features and critical design issues are discussed, and projected performances outlined.
Date: September 1, 1996
Creator: Makowski, M.; Bosia, G. & Elio, F.
Partner: UNT Libraries Government Documents Department
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Initial results from a folded waveguide ICRF antenna development project

Description: A folded waveguide (FWG) ICRF launcher has been built and preliminary high power tests completed. This project is intended to provide a proof-of-principle test, using a high density plasma load, of the high power density capability and other ITER-relevant advanced features of the FWG. The design is a 12 vane, 57 MHz unit with a quarter-wavelength resonator configuration. This FWG has a 0.31 m square cross section that can be installed with either fast wave or ion-Bernstein wave polarization and… more
Date: August 1, 1997
Creator: Bigelow, T. S.; Cole, M. J. & Fadnek, A.
Partner: UNT Libraries Government Documents Department
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RF heating experiments in CHS and RF development for LHD

Description: The Lame Helical Device, LHD, is in its final construction phase. It is a 1=2, m=10 Heliotron/Torsatron type helical system with a major radius of 4 m. The compact helical system, CHS, is a 1=2, m=8 helical system of the same type with a major radius of 1m. CHS has been used for supporting experiments to clarify physics issues of helical systems and to examine the key ideas which will be applied to LHD. This paper summarizes the experimental results of those supporting experiments in CHS and ho… more
Date: April 1, 1997
Creator: Watari, T.; Kumazawa, R. & Nishimura, K.
Partner: UNT Libraries Government Documents Department
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Development of impedance matching technologies for ICRF antenna arrays

Description: All high power ICRF heating systems include devices for matching the input impedance of the antenna array to the generator output impedance. For most types of antennas used, the input impedance is strongly time-dependent on timescales as rapid as 10-4 s, while the rf generators used are capable of producing full power only into a stationary load impedance. Hence, the dynamic response of the matching method is of great practical importance. In this paper, world-wide developments in this field ov… more
Date: March 1998
Creator: Pinsker, R. I.
Partner: UNT Libraries Government Documents Department
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Alpha-physics and measurement requirements for ITER

Description: This paper reviews alpha particle physics issues in ITER and their implications for alpha particle measurements. A comparison is made between alpha heating in ITER and NBI and ICRH heating systems in present tokamaks, and alpha particle issues in ITER are discussed in three physics areas: `single particle` alpha effects, `collective` alpha effects, and RF interactions with alpha particles. 29 refs., 4 figs., 4 tabs.
Date: December 31, 1995
Creator: Zweben, S. J.; Young, K. M.; Putvinski, S.; Petrov, M. P.; Sadler, G. & Tobita, K.
Partner: UNT Libraries Government Documents Department
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