High performance plasmas on the National Spherical Torus Experiment

D. A. Gates, M. G. Bell, R. E. Bell, J. Bialek, T. Bigelow, M. Bitter, P. Bonoli, D. Darrow, P. Efthimion, J. Ferron, E. Fredrickson, L. Grisham, J. Hosea, D. Johnson, R. Kaita, S. Kaye, S. Kubota, H. Kugel, B. LeBlanc, R. MaingiJ. Manickam, T. K. Mau, R. J. Maqueda, E. Mazzucato, J. Menard, D. Mueller, B. Nelson, N. Nishino, M. Ono, F. Paoletti, S. Paul, Y. K.M. Peng, C. K. Phillips, R. Raman, P. Ryan, S. A. Sabbagh, M. Schaffer, C. H. Skinner, D. Stutman, D. Swain, E. Synakowski, Y. Takase, J. Wilgen, J. R. Wilson, W. Zhu, S. Zweben, A. Bers, M. Carter, B. Deng, C. Domier, E. Doyle, M. Finkenthal, K. Hill, T. Jarboe, S. Jardin, H. Ji, L. Lao, K. C. Lee, N. Luhmann, R. Majeski, H. Park, T. Peebles, R. I. Pinsker, G. Porter, A. Ram, M. Rensink, T. Rognlien, D. Stotler, B. Stratton, G. Taylor, W. Wampler, G. A. Wurden, X. Q. Xu, L. Zeng

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The National Spherical Torus Experiment has produced toroidal plasmas at low aspect ratio (A = R/a = 0.86m/0.68m ∼ 1.3, where R is the major radius and a is the minor radius of the torus) with plasma currents of 1.4MA. The rapid development of the machine has led to very exciting physics results during the first full year of physics operation. Pulse lengths in excess of 0.5s have been obtained with inductive current drive. Up to 4MW of High Harmonic Fast Wave (HHFW) heating power has been applied with 6MW planned. Using only 2MW of HHFW heating power clear evidence of electron heating is séen with HHFW, as observed by the multi point Thomson scattering diagnostic. A non-inductive current drive concept known as Coaxial Helicity Injection (CHI) has driven 260kA of toroidal current. Neutral beam heating power of 5MW has been injected. Plasmas with βt (=2μo

/B2 = a measure of magnetic confinement efficiency) of 22% have been achieved, as calculated using the EFIT equilibrium reconstruction code, β limiting phenomena have been observed, and the maximum βt scales with IpaBt. High frequency (>MHz) magnetic fluctuations have been observed. H-mode plasmas are observed with confinement times of > 100ms. Beam heated plasmas show energy confinement times in excess of those predicted by empirical scaling expressions. Ion temperatures in excess of 2.0keV have been measured, and power balance suggests that the power loss from the ions to the electrons may exceed the calculated classical input power to the ions.

Original languageEnglish (US)
Title of host publicationPPPS 2001 - Pulsed Power Plasma Science 2001
EditorsRobert Reinovsky, Mark Newton
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
ISBN (Electronic)0780371208, 9780780371200
StatePublished - 2015
Event28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference, PPPS 2001 - Las Vegas, United States
Duration: Jun 17 2001Jun 22 2001

Publication series

NamePPPS 2001 - Pulsed Power Plasma Science 2001


Other28th IEEE International Conference on Plasma Science and 13th IEEE International Pulsed Power Conference, PPPS 2001
Country/TerritoryUnited States
CityLas Vegas

All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Nuclear Energy and Engineering
  • Nuclear and High Energy Physics


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