Edge radial electric field structure and its connections to H-mode confinement in Alcator C-Mod plasmas

By R. McDermott, B. Lipschultz, J. Hughes, P. Catto, A. Hubbard, Ian H. Hutchinson, R. Granetz, Martin Greenwald, B. LaBombard, K. Marr and 4 more. 2009

166 citations recorded by the source corpus.

High-resolution charge-exchange recombination spectroscopic measurements of B5+ ions have enabled the first spatially resolved calculations of the radial electric field (Er) in the Alcator C-Mod pedestal region [E. S. Marmar, Fusion Sci. Technol. 51, 261 (2006)]. These observations offer new challenges for theory and simulation and provide for important comparisons with other devices. Qualitatively, the field structure observed on C-Mod is similar to that on other tokamaks. However, the narrow high-confinement mode (H-mode) Er well widths (5 mm) observed on C-Mod suggest a scaling with machine size, while the observed depths (up to 300 kV/m) are unprecedented. Due to the strong ion-electron thermal coupling in the C-Mod pedestal, it is possible to infer information about the main ion population in this region. The results indicate that in H-mode the main ion pressure gradient is the dominant contributor to the Er well and that the main ions have significant edge flow. C-Mod H-mode data show a clear correl...

Subfields: Materials Chemistry, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/156ee325bf94c32c872c00d90950169852b4dfab