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

*This work was supported by JSPS Grant-in-Aid for Scientific Research(C) 16K06947 and the U.S. DOE under DE-FC02-04ER54698.

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)