Suppression of electron temperature gradient turbulence via negative magnetic shear in NSTX


Journal Article

Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regime. Density fluctuation measurements from high-k microwave scattering are verified to be the electron temperature gradient (ETG) mode by matching measured rest frequency and linear growth rate to gyrokinetic calculations. Fluctuation suppression under negligible E×B shear conditions confirm that negative magnetic shear alone is sufficient for ETG suppression. Measured electron temperature gradients can significantly exceed ETG critical gradients with ETG mode activity reduced to intermittent bursts, while electron thermal diffusivity improves to below 0.1 electron gyro-Bohms. © 2011 American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Yuh, HY; Kaye, SM; Levinton, FM; Mazzucato, E; Mikkelsen, DR; Smith, DR; Bell, RE; Hosea, JC; Leblanc, BP; Peterson, JL; Park, HK; Lee, W

Published Date

  • February 3, 2011

Published In

Volume / Issue

  • 106 / 5

Electronic International Standard Serial Number (EISSN)

  • 1079-7114

International Standard Serial Number (ISSN)

  • 0031-9007

Digital Object Identifier (DOI)

  • 10.1103/PhysRevLett.106.055003

Citation Source

  • Scopus