H-mode research in NSTX

  • R. Maingi
  • , M. G. Bell
  • , R. E. Bell
  • , C. E. Bush
  • , E. D. Fredrickson
  • , D. A. Gates
  • , T. Gray
  • , D. W. Johnson
  • , R. Kaita
  • , S. M. Kaye
  • , S. Kubota
  • , H. W. Kugel
  • , C. J. Lasnier
  • , B. P. LeBlanc
  • , R. J. Maqueda
  • , D. Mastrovito
  • , J. E. Menard
  • , D. Mueller
  • , M. Ono
  • , F. Paoletti
  • S. J. Paul, Y. K.M. Peng, A. L. Roquemore, S. A. Sabbagh, C. H. Skinner, V. A. Soukhanovskii, D. Stutman, D. W. Swain, E. J. Synakowski, T. Tan, J. B. Wilgen, S. J. Zweben

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

H-modes are routinely obtained in the National Spherical Torus Experiment (NSTX) and have become a standard operational scenario. L-H transitions triggered by NBI heating have been obtained over a wide parameter range in Ip, Bt, and n̄e in either lower-single-null (LSN) or double-null (DN) diverted discharges. Edge localized modes are observed in both configurations but the characteristics differ between DN and LSN, which also have different triangularities (δ). An H-mode duration of 500 ms was obtained in LSN, with a total pulse length of ∼1 s. Preliminary power threshold studies indicate that the L-H threshold is between 600 kW and 1.2 MW, depending on the target parameters. Gas injector fuelling from the centre stack (i.e. the high toroidal field side) has enabled routing H-mode access, and comparisons with low-field side (LFS) fuelled H-mode discharges show that the LFS fuelling delays the L-H transition and alters the pre-transition plasma profiles. Gas puff imaging and reflectometry show that the H-mode edge is usually more quiescent than the L-mode edge. Divertor infrared camera measurements indicate up to 70% of available power flows to the divertor targets in quiescent H-mode discharges.

Original languageEnglish
Pages (from-to)969-974
Number of pages6
JournalNuclear Fusion
Volume43
Issue number9
DOIs
StatePublished - Sep 2003
Externally publishedYes

Fingerprint

Dive into the research topics of 'H-mode research in NSTX'. Together they form a unique fingerprint.

Cite this