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Lao LL, John HES, Peng Q, Ferron JR, Strait EJ, Taylor TS, Meyer WH, Zhang C, You KI. MHD Equilibrium Reconstruction in the DIII-D Tokamak. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst48-968] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- L. L. Lao
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - H. E. St. John
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - Q. Peng
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - J. R. Ferron
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - E. J. Strait
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - T. S. Taylor
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - W. H. Meyer
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - C. Zhang
- Chinese Academy of Science, Institute of Plasma Physics, Hefei, Anhui, China
| | - K. I. You
- Korean Basic Science Institute, National Fusion Research Center, Daejeon, Korea
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Raman R, Jarboe TR, Nelson BA, Gerhardt SP, Lay WS, Plunkett GJ. Design and operation of a fast electromagnetic inductive massive gas injection valve for NSTX-U. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:11E801. [PMID: 25430366 DOI: 10.1063/1.4885545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Results from the operation of an electromagnetic valve, that does not incorporate ferromagnetic materials, are presented. Image currents induced on a conducting disc placed near a pancake solenoid cause it to move away from the solenoid and open the vacuum seal. A new and important design feature is the use of Lip Seals for the sliding piston. The pressure rise in the test chamber is measured directly using a fast time response Baratron gauge. The valve injects over 200 Torr l of nitrogen in less than 3 ms, which remains unchanged at moderate magnetic fields.
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Affiliation(s)
- R Raman
- William E. Boeing Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - T R Jarboe
- William E. Boeing Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - B A Nelson
- William E. Boeing Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - S P Gerhardt
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - W-S Lay
- William E. Boeing Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - G J Plunkett
- William E. Boeing Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
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Victor BS, Jarboe TR, Hossack AC, Ennis DA, Nelson BA, Smith RJ, Akcay C, Hansen CJ, Marklin GJ, Hicks NK, Wrobel JS. Evidence for separatrix formation and sustainment with steady inductive helicity injection. PHYSICAL REVIEW LETTERS 2011; 107:165005. [PMID: 22107397 DOI: 10.1103/physrevlett.107.165005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Indexed: 05/31/2023]
Abstract
The first sustainment of toroidal plasma current of 50 kA at up to 3 times the injected currents, added in quadrature, using steady inductive helicity injection is described. Separatrix currents-currents not linking the helicity injectors-are sustained up to 40 kA. Decreases in the n=1 toroidal mode of the poloidal magnetic field at higher current amplifications indicate more quiescent, direct toroidal current drive. Results are achieved in HIT-SI (with a spheromak of major radius 0.3 m) during deuterium operations immediately after helium operation. These results represent a breakthrough in the development of this new current drive method for magnetic confinement fusion.
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Affiliation(s)
- B S Victor
- University of Washington, Seattle, Washington 98105, USA
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Battaglia DJ, Bongard MW, Fonck RJ, Redd AJ, Sontag AC. Tokamak startup using point-source dc helicity injection. PHYSICAL REVIEW LETTERS 2009; 102:225003. [PMID: 19658871 DOI: 10.1103/physrevlett.102.225003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Indexed: 05/28/2023]
Abstract
Startup of a 0.1 MA tokamak plasma is demonstrated on the ultralow aspect ratio Pegasus Toroidal Experiment using three localized, high-current density sources mounted near the outboard midplane. The injected open field current relaxes via helicity-conserving magnetic turbulence into a tokamaklike magnetic topology where the maximum sustained plasma current is determined by helicity balance and the requirements for magnetic relaxation.
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Affiliation(s)
- D J Battaglia
- Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, Wisconsin 53706, USA
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Hsu SC, Tang XZ. Proposed Experiment to Study Relaxation Formation of a Spherical Tokamak with a Plasma Center Column. JOURNAL OF FUSION ENERGY 2006. [DOI: 10.1007/s10894-006-9032-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Tang XZ, Boozer AH. Constrained resonance in magnetic self-organization. PHYSICAL REVIEW LETTERS 2005; 95:155002. [PMID: 16241732 DOI: 10.1103/physrevlett.95.155002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Indexed: 05/05/2023]
Abstract
In a linear driven problem with integral constraints, resonant phenomena can still persist but occur away from the fundamental frequencies of the unconstrained linear system. The frequency and the mode structure of the constrained resonances are found to be the intrinsic properties of the undriven and unconstrained linear systems. This is shown with a Taylor-relaxed magnetized plasma in a torus that conserves the net toroidal flux. The constrained resonance leads to a number of modifications to the standard paradigm of Taylor relaxation in a toroidal plasma.
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Affiliation(s)
- X Z Tang
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Jardin S, Kessel C, Menard J, Mau T, Miller R, Najmabadi F, Chan V, Lao L, Linliu Y, Miller R, Petrie T, Politzer P, Turnbull A. Physics basis for a spherical torus power plant. FUSION ENGINEERING AND DESIGN 2003. [DOI: 10.1016/s0920-3796(02)00303-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Cheng E, Peng Y, Cerbone R, Fogarty P, Galambos JD, Mogahed E, Nelson B, Simnad M, Sviatoslavsky I, Tillack M. Study of a spherical tokamak based volumetric neutron source. FUSION ENGINEERING AND DESIGN 1998. [DOI: 10.1016/s0920-3796(97)00096-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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