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Spong DA, Heidbrink WW, Paz-Soldan C, Du XD, Thome KE, Van Zeeland MA, Collins C, Lvovskiy A, Moyer RA, Austin ME, Brennan DP, Liu C, Jaeger EF, Lau C. First Direct Observation of Runaway-Electron-Driven Whistler Waves in Tokamaks. Phys Rev Lett 2018; 120:155002. [PMID: 29756886 DOI: 10.1103/physrevlett.120.155002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Indexed: 06/08/2023]
Abstract
DIII-D experiments at low density (n_{e}∼10^{19} m^{-3}) have directly measured whistler waves in the 100-200 MHz range excited by multi-MeV runaway electrons. Whistler activity is correlated with runaway intensity (hard x-ray emission level), occurs in novel discrete frequency bands, and exhibits nonlinear limit-cycle-like behavior. The measured frequencies scale with the magnetic field strength and electron density as expected from the whistler dispersion relation. The modes are stabilized with increasing magnetic field, which is consistent with wave-particle resonance mechanisms. The mode amplitudes show intermittent time variations correlated with changes in the electron cyclotron emission that follow predator-prey cycles. These can be interpreted as wave-induced pitch angle scattering of moderate energy runaways. The tokamak runaway-whistler mechanisms have parallels to whistler phenomena in ionospheric plasmas. The observations also open new directions for the modeling and active control of runaway electrons in tokamaks.
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Affiliation(s)
- D A Spong
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W W Heidbrink
- University of California-Irvine, Irvine, California 92697, USA
| | - C Paz-Soldan
- General Atomics, San Diego, California 92186-5608, USA
| | - X D Du
- University of California-Irvine, Irvine, California 92697, USA
| | - K E Thome
- Oak Ridge Associated Universities, P.O. Box 117, Oak Ridge, Tennessee 37831, USA
| | | | - C Collins
- General Atomics, San Diego, California 92186-5608, USA
| | - A Lvovskiy
- Oak Ridge Associated Universities, P.O. Box 117, Oak Ridge, Tennessee 37831, USA
| | - R A Moyer
- University of California-San Diego, La Jolla, California 92093, USA
| | - M E Austin
- University of Texas, Austin, Texas 78705, USA
| | - D P Brennan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C Liu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - E F Jaeger
- XCEL Engineering, Oak Ridge, Tennessee 37830, USA
| | - C Lau
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Perkins RJ, Hosea JC, Kramer GJ, Ahn JW, Bell RE, Diallo A, Gerhardt S, Gray TK, Green DL, Jaeger EF, Jaworski MA, LeBlanc BP, McLean A, Maingi R, Phillips CK, Roquemore L, Ryan PM, Sabbagh S, Taylor G, Wilson JR. High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX. Phys Rev Lett 2012; 109:045001. [PMID: 23006093 DOI: 10.1103/physrevlett.109.045001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Indexed: 06/01/2023]
Abstract
A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.
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Affiliation(s)
- R J Perkins
- Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA.
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Jaeger EF, Berry LA, Myra JR, Batchelor DB, D'Azevedo E, Bonoli PT, Phillips CK, Smithe DN, D'Ippolito DA, Carter MD, Dumont RJ, Wright JC, Harvey RW. Sheared poloidal flow driven by mode conversion in tokamak plasmas. Phys Rev Lett 2003; 90:195001. [PMID: 12785951 DOI: 10.1103/physrevlett.90.195001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Indexed: 05/24/2023]
Abstract
A two-dimensional integral full-wave model is used to calculate poloidal forces driven by mode conversion in tokamak plasmas. In the presence of a poloidal magnetic field, mode conversion near the ion-ion hybrid resonance is dominated by a transition from the fast magnetosonic wave to the slow ion cyclotron wave. The poloidal field generates strong variations in the parallel wave spectrum that cause wave damping in a narrow layer near the mode conversion surface. The resulting poloidal forces in this layer drive sheared poloidal flows comparable to those in direct launch ion Bernstein wave experiments.
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Affiliation(s)
- E F Jaeger
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071, USA
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Carter MD, Baity FW, Barber GC, Goulding RH, Mori Y, Sparks DO, White KF, Jaeger EF, Chang-Díaz F, Squire JP. Comparing Experiments with Modeling to Optimize Light Ion Helicon Plasma Sources for VASIMR. Fusion Science and Technology 2003. [DOI: 10.13182/fst03-a11963578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M. D. Carter
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - F. W. Baity
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - G. C. Barber
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | - Y. Mori
- Kyushu University, Kasuga-city, Fukuoka, Japan
| | - D. O. Sparks
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - K. F. White
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - E. F. Jaeger
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | - J. P. Squire
- Advanced Space Propulsion Laboratory, Houston, Texas
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Schmidt JA, Thomassen KI, Goldston RJ, Neilson GH, Nevins WM, Sinnis JC, Andersen P, Bair W, Barr WL, Batchelor DB, Baxi C, Berg G, Bernabei S, Bialek JM, Bonoli PT, Boozer A, Bowers D, Bronner G, Brooks JN, Brown TG, Bulmer R, Butner D, Campbell R, Casper T, Chaniotakis E, Chaplin M, Chen SJ, Chin E, Chrzanowski J, Citrolo J, Cole MJ, Dahlgren F, Davis FC, Davis J, Davis S, Diatchenko N, Dinkevich S, Feldshteyn Y, Felker B, Feng T, Fenstermacher ME, Fleming R, Fogarty PJ, Fragetta W, Fredd E, Gabler M, Galambos J, Gohar Y, Goranson PL, Greenough N, Grisham LR, Haines J, Haney S, Hassenzahl W, Heim J, Heitzenroeder PJ, Hill DN, Hodapp T, Houlberg WA, Hubbard A, Hyatt A, Jackson M, Jaeger EF, Jardin SC, Johnson J, Jones GH, Juliano DR, Junge R, Kalish M, Kessel CE, Knutson D, LaHaye RJ, Lang DD, Langley RA, Liew SL, Lu E, Mantz H, Manickam J, Mau TK, Medley S, Mikkelsen DR, Miller R, Monticello D, Morgan D, Moroz P, Motloch C, Mueller J, Myatt L, Nelson BE, Neumeyer CL, Nilson D, O'Conner T, Pearlstein LD, Peebles WA, Pelovitz M, Perkins FW, Perkins LJ, Petersen D, Pillsbury R, Politzer PA, Pomphrey N, Porkolab M, Posey A, Radovinsky A, Raftopoulis S, Ramakrishnan S, Ramos J, Rauch W, Ravenscroft D, Redler K, Reiersen WT, Reiman A, Reis E, Rewoldt G, Richards DJ, Rocco R, Rognlien TD, Ruzic D, Sabbagh S, Sapp J, Sayer RO, Scharer JE, Schmitz L, Schnitz J, Sevier L, Shipley SE, Simmons RT, Slack D, Smith GR, Stambaugh R, Steill G, Stevenson T, Stoenescu S, Onge KTS, Stotler DP, Strait T, Strickler DJ, Swain DW, Tang W, Tuszewski M, Ulrickson MA, VonHalle A, Walker MS, Wang C, Wang P, Warren J, Werley KA, West WP, Williams F, Wong R, Wright K, Wurden GA, Yugo JJ, Zakharov L, Zbasnik J. The design of the Tokamak Physics Experiment (TPX). J Fusion Energ 1993. [DOI: 10.1007/bf01079667] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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