Effects of Magnetic Coil Misalignments on the SAS Divertor

POSTER

Abstract

A new Small Angle Slot (SAS) divertor has recently been installed and tested in DIII-D, promising easier plasma detachment and lower target temperatures. Previous SAS analyses focused on the accuracy of the 2D reconstructed strike geometry and 3D ``vacuum'' analyses of RMPs on the lobes and on the strike point modulation. The present work introduces a kinetic EFIT 2D equilibrium reconstructed from a recent 2017 SAS experiment. The kinetic EFIT and its ``vacuum'' topology due to 3D error and perturbation fields are compared to the previous analyses based on a synthetic equilibrium, showing similar results. The magnetic lobes remain confined within the SAS and the toroidal modulation of the strike point position is only slightly affected. Further simulations of a possible shift of the toroidal field coil are carried out through 3D field-line tracing. The effects of such misalignments including plasma response on the SAS are discussed, together with the corresponding implications for the design of the next envisaged SAS upgrade.

*Work supported by US DOE under DE-FC02-04ER54698 and DE-FG02-95ER54309.

Authors

  • G.L. Trevisan

    • Oak Ridge Associated Universities
  • B.C. Lyons

    • General Atomics, Oak Ridge Associated Universities
    • Oak Ridge Associated Universities
  • L.L. Lao

    • General Atomics
    • GA
  • T. Evans

    • General Atomics
    • GA
  • Houyang Guo

    • General Atomics
    • GA, US
    • GA
    • General Atomics - San Diego
  • Yueqiang Liu

    • General Atomics
  • W. Wu

    • General Atomics
  • D.M. Orlov

    • UCSD
    • University of California-San Diego
  • Andreas Wingen

    • Oak Ridge National Laboratory
    • Oak Ridge Nt'l Lab.