Observations of Reduced Electron Gyro-scale Fluctuations in National Spherical Torus Experiment H-mode Plasmas with Large E × B Flow Shear
Authors: D.R. Smith, S.M. Kaye, W. Lee, E. Mazzucato, H.K. Park, R.E. Bell, C. W. Domier, B.P. LeBlanc, F.M. Levinton, N.C. Luhmann, Jr., J.E. Menard, and H. Yu
Abstract:
Electron gyro-scale fluctuation measurements in National Spherical Torus Experiment (NSTX) H-mode plasmas with large toroidal rotation reveal fluctuations consistent with electron temper- ature gradient (ETG) turbulence. Large toroidal rotation in NSTX plasmas with neutral beam injection generates E × B flow shear rates comparable to ETG linear growth rates. Enhanced fluctuations occur when the electron temperature gradient is marginally stable with respect to the ETG linear critical gradient. Fluctuation amplitudes decrease when the E × B flow shear rate exceeds ETG linear growth rates. The observations indicate E × B flow shear can be an effective suppression mechanism for ETG turbulence.
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Submitted to: Physical Review Letters, (January 2009)
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