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Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment

Publication ,  Journal Article
Peterson, JL; Bell, R; Candy, J; Guttenfelder, W; Hammett, GW; Kaye, SM; Leblanc, B; Mikkelsen, DR; Smith, DR; Yuh, HY
Published in: Physics of Plasmas
May 1, 2012

The National Spherical Torus Experiment (NSTX) [M. Ono, Nucl. Fusion 40, 557 (2000)] can achieve high electron plasma confinement regimes that are super-critically unstable to the electron temperature gradient driven (ETG) instability. These plasmas, dubbed electron internal transport barriers (e-ITBs), occur when the magnetic shear becomes strongly negative. Using the gyrokinetic code GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)], the first nonlinear ETG simulations of NSTX e-ITB plasmas reinforce this observation. Local simulations identify a strongly upshifted nonlinear critical gradient for thermal transport that depends on magnetic shear. Global simulations show e-ITB formation can occur when the magnetic shear becomes strongly negative. While the ETG-driven thermal flux at the outer edge of the barrier is large enough to be experimentally relevant, the turbulence cannot propagate past the barrier into the plasma interior. © 2012 American Institute of Physics.

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Published In

Physics of Plasmas

DOI

ISSN

1070-664X

Publication Date

May 1, 2012

Volume

19

Issue

5

Related Subject Headings

  • Fluids & Plasmas
  • 5109 Space sciences
  • 5106 Nuclear and plasma physics
  • 0203 Classical Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
  • 0201 Astronomical and Space Sciences
 

Citation

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Peterson, J. L., Bell, R., Candy, J., Guttenfelder, W., Hammett, G. W., Kaye, S. M., … Yuh, H. Y. (2012). Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment. Physics of Plasmas, 19(5). https://doi.org/10.1063/1.4718456
Peterson, J. L., R. Bell, J. Candy, W. Guttenfelder, G. W. Hammett, S. M. Kaye, B. Leblanc, D. R. Mikkelsen, D. R. Smith, and H. Y. Yuh. “Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment.” Physics of Plasmas 19, no. 5 (May 1, 2012). https://doi.org/10.1063/1.4718456.
Peterson JL, Bell R, Candy J, Guttenfelder W, Hammett GW, Kaye SM, et al. Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment. Physics of Plasmas. 2012 May 1;19(5).
Peterson, J. L., et al. “Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment.” Physics of Plasmas, vol. 19, no. 5, May 2012. Scopus, doi:10.1063/1.4718456.
Peterson JL, Bell R, Candy J, Guttenfelder W, Hammett GW, Kaye SM, Leblanc B, Mikkelsen DR, Smith DR, Yuh HY. Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment. Physics of Plasmas. 2012 May 1;19(5).

Published In

Physics of Plasmas

DOI

ISSN

1070-664X

Publication Date

May 1, 2012

Volume

19

Issue

5

Related Subject Headings

  • Fluids & Plasmas
  • 5109 Space sciences
  • 5106 Nuclear and plasma physics
  • 0203 Classical Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
  • 0201 Astronomical and Space Sciences