1. Regime of very high confinement in the boronized DIII-D tokamak
- Author
-
L. L. Lao, R. J. Groebner, C. M. Greenfield, A. D. Turnbull, T.H. Osborne, E.A. Lazarus, S.I. Lippmann, J.C. DeBoo, D.P. Schissel, J.C. Phillips, T.W. Petrie, Diii-D Team, E. J. Strait, K.L. Holtrop, W.P. West, Keith H. Burrell, T. S. Taylor, G.L. Jackson, T. Hodapp, R.A. James, and J. Winter
- Subjects
Physics ,Surface coating ,Tokamak ,DIII-D ,Impurity ,law ,General Physics and Astronomy ,Electron temperature ,Plasma ,Atomic physics ,Scaling ,Ion ,law.invention - Abstract
Following boronization, tokamak discharges in DIII-D have been obtained with confinement times up to a factor of 3.5 above the ITER89-P L-mode scaling and 1.8 times greater than the DIII-D/JET H-mode scaling relation. Very high confinement phases are characterized by relatively high central density with ${\mathit{n}}_{\mathit{e}}$(0)\ensuremath{\approxeq}1\ifmmode\times\else\texttimes\fi{}${10}^{20}$ ${\mathrm{m}}^{\mathrm{\ensuremath{-}}3}$, and central ion temperatures up to 13.6 keV at moderate plasma currents (1.6 MA) and heating powers (12.5--15.3 MW). These discharges exhibit a low fraction of radiated power, P\ensuremath{\le}25%, ${\mathit{Z}}_{\mathit{e}\mathit{f}\mathit{f}}$(0) close to unity, and lower impurity influxes than comparable DIII-D discharges before boronization.
- Published
- 1991