Rotation Reversal Bifurcation and Energy Confinement Saturation in Tokamak Ohmic L-Mode Plasmas

Rotation Reversal Bifurcation and Energy Confinement Saturation in Tokamak Ohmic L-Mode Plasmas

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Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator C-Mod Ohmic L-mode plasmas following electron density ramps. For low density discharges, the core rotation is directed cocurrent, and reverses to countercurrent following an increase in the density above a cert...

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Bibliographic Details
Main Authors: Rice, John E., Cziegler, Istvan, Diamond, P. H., Duval, B. P., Podpaly, Yuri A., Reinke, Matthew Logan, Ennever, Paul Chappell, Greenwald, Martin J., Hughes, Jerry W., Ma, Y., Marmar, Earl S., Porkolab, Miklos, Tsujii, Naoto, Wolfe, Stephen M.
Other Authors: Massachusetts Institute of Technology. Plasma Science and Fusion Center
Format: Article
Language:en_US
Published: American Physical Society (APS) 2012
Online Access:http://hdl.handle.net/1721.1/69598
https://orcid.org/0000-0003-3234-8733
https://orcid.org/0000-0002-9518-4097
https://orcid.org/0000-0002-4438-729X
https://orcid.org/0000-0002-5283-0546
Description
Summary:Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator C-Mod Ohmic L-mode plasmas following electron density ramps. For low density discharges, the core rotation is directed cocurrent, and reverses to countercurrent following an increase in the density above a certain threshold. Such reversals occur together with a decrease in density fluctuations with 2  cm[superscript -1]≤k[subscript θ]≤11  cm[superscript -1] and frequencies above 70 kHz. There is a strong correlation between the reversal density and the density at which the Ohmic L-mode energy confinement changes from the linear to the saturated regime.

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