Published May 1991 | Version v1
Report Open

Limiter H-mode experiments on TFTR

Creators

  • 1. Oak Ridge National Lab., TN (USA)
  • 2. Princeton Univ., NJ (USA). Plasma Physics Lab.
  • 3. Los Alamos National Lab., NM (USA)
  • 4. Wisconsin Univ., Madison, WI (USA)
  • 5. College de France, 75 - Paris (France). Lab. de Physique Atomique et Moleculaire
  • 6. Fusion Physics and Technologies, Torrance, CA (USA)
  • 7. Massachusetts Inst. of Tech., Cambridge, MA (USA)
  • 8. Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)
  • 9. Columbia Univ., New York, NY (USA)
  • 10. Tokyo Univ. (Japan)
  • 11. Canadian Fusion Fuels Technology Project, Toronto, ON (Canada)

Description

Limiter H-modes with centrally peaked density profiles have been obtained in TFTR using a highly conditioned graphite limiter. The transition to these centrally peaked H-modes takes place from the supershot to the H-mode rather than the usual L- to H-mode transition observed on other tokamaks. Bidirectional beam heating is required to induce the transition. Density peaking factors, ne(0)/, greater than 2.3 are obtained and at the same time the H-mode characteristics are similar to those of limiter H-modes on other tokamaks, while the global confinement, τE, can be >2.5 times L-mode scaling. The transport analysis of the data shows that transport in these H-modes is similar to that of supershots within the inner 0.6 m core of the plasma, but the stored electron energy (calculated using measured values of Te and ne) is higher for the H-mode at the plasma edge. Microwave scattering data for the edge plasma shows broad spectra at k = 5.5 cm-1 which begin at the drop in Dα radiation and are strongly shifted in the electron diamagnetic drift direction. At the same time, beam emission spectroscopy (BES) shows a coherent mode near the boundary which propagates in the ion direction with m = 15--20 at 20--30 kHz. During the ELM event these apparent rotations cease and Mirnov fluctuations in the frequency range of 50--500 kHz increase in intensity. 16 refs., 8 figs

Availability note (English)

MF available from INIS under the Report Number; OSTI as DE91012309; NTIS; INIS; US Govt. Printing Office Dep.

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Additional details

Publishing Information

Imprint Pagination
21 p.
Report number
PPPL--2743

Optional Information

Contract/Grant/Project number
Contract AC02-76CH03073
Funding organization
USDOE, Washington, DC (USA).