Pedestal profiles and fluctuations in C-Mod enhanced D-alpha H-modes : The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics
Hubbard, A. E. ; Boivin, R. L. ; Granetz, R. S. ; Greenwald, M. ; Hughes, J. W. ; Hutchinson, I. H. ; Irby, J. ; LaBombard, B. ; Lin, Y. ; Marmar, E. S. ; Mazurenko, A. ; Mossessian, D. ; Nelson-Melby, E. ; Porkolab, M. ; Snipes, J. A. ; Terry, J. ; Wolfe, S. ; Wukitch, S.
[S.l.] : American Institute of Physics (AIP)
Published 2001
[S.l.] : American Institute of Physics (AIP)
Published 2001
| ISSN: |
1089-7674
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
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| Notes: |
High resolution measurements on the Alcator C-Mod tokamak [I. H. Hutchinson et al., Phys. Plasmas 1, 1551 (1994)] of the transport barrier in the "Enhanced Dα" (EDA) regime, which has increased particle transport without large edge localized modes, show steep density and temperature gradients over a region of 2–5 mm, with peak pressure gradients up to 12 MPa/m. Evolution of the pedestal at the L-H transition is consistent with a large, rapid drop in thermal conductivity across the barrier. A quasi-coherent fluctuation in density, potential, and Bpol, with f0∼50–150 kHz and kθ∼4 cm−1, always appears in the barrier during EDA, and drives a large particle flux. Conditions to access the steady-state EDA regime in deuterium include δ〉0.35, q95〉3.5, and L-mode target density n¯e〉1.2×1020 m−3. A reduced q95 limit is found for hydrogen discharges. © 2001 American Institute of Physics.
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| Type of Medium: |
Electronic Resource
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| URL: |