Magnetic shear effect on plasma transport in ECH injected DIII-D plasma

POSTER

Abstract

The effect of magnetic shear on plasma transport for Te/Ti near unity has been explored in DIII-D during ECH. Previous reports showed that significant confinement degradation occurs at Te/Ti~1 in positive shear (PS) plasmas in DIII-D and JT-60U [1,2], whereas confinement degradation is reduced at Te/Ti~1 in negative central shear (NCS) plasmas [1]. In this study, plasma transport in weak magnetic shear (WS) plasmas with ECH is investigated and compared with that in NCS and PS plasmas. Weak magnetic shear is found to be effective in minimizing degradation of ion thermal confinement as Te/Ti increases through ECH application, and an improved confinement factor of H98y2~1.2 is maintained, similar to NCS plasmas. During ECH, the ion thermal diffusivity in the core region becomes smaller with decreasing magnetic shear and the density and toroidal rotation in the core region tend to be steeper in the negative shear region. The variation in plasma transport will be investigated using gyro-kinetic simulations.

[1]M. Yoshida et al Nucl. Fusion 57 (2017) 056027

[2]G.R. McKee et al 25th IAEA FEC (St Petersburg, Russia, 2014) EX/2-2

Presenters

  • Maiko Yoshida

    National Institutes for Quantum and Radiological Science and Technology (QST)

Authors

  • Maiko Yoshida

    National Institutes for Quantum and Radiological Science and Technology (QST)

  • George R Mckee

    Univ of Wisconsin, Madison, Univ of Wisconsin, Madison, Univ of Wisconsin, Madison, University of Wisconsin–Madison, University of Wisconsin-Madison, University of Wisconsin - Madison, University of Wisconsin, Madison, Univ. of Wisconsin, Madison

  • Andrea MV Garofalo

    General Atomics - San Diego, General Atomics

  • C Craig Petty

    General Atomics, General Atomics - San Diego, GA

  • Motoki Nakata

    National Institute for Fusion Sciences

  • B.A. A Grierson

    PPPL, Princeton Plasma Phys Lab, Princeton Plasma Physics Laboratory

  • Darin R Ernst

    Massachusetts Inst of Tech-MIT

  • Terry L Rhodes

    Univ of California - Los Angeles, University of California, Los Angeles, UCLA, University of California Los Angeles

  • Christopher T Holcomb

    Lawrence Livermore Natl Lab, LLNL

  • Makoto Ono

    National Institutes for Quantum and Radiological Science and Technology, National Institutes for Quantum and Radiological Science and Technology (QST)