Edge turbulence in DIII-D plasmas with strong negative triangularity shaping

POSTER

Abstract

In the DIII-D 2023 experimental campaign, plasmas with strong negative triangularity shaping with an average triangularity ~-0.5 have demonstrated high performance similar to the conventional positive triangularity shape H-modes and in the absence of edge localized modes (ELMs). This work presents broadband fluctuations of electron temperature (Te) from correlation electron cyclotron emission at the edge of these plasmas, as well as density (ne) turbulence and turbulence poloidal flow velocities from Doppler backscattering in a radial range of ρ~0.85-1.0. It is observed that Te turbulence has a much larger (generally more than 2-3 times) amplitude in negative triangularity than that in conventional H-mode plasmas. The radial correlation length in Te turbulence is typically 5-10 times of the ion gyro-radius, similar to that in the conventional L-mode plasmas. The RMS fluctuation level of the Te and ne turbulence exhibits a peaking radial profile feature, and the peaks roughly coincide with the radial electric field well near ρ~0.95 inferred from the poloidal flow velocity of the ne turbulence. Results of linear stability turbulence simulations will also be presented.

*Work is supported by USDOE Grants DE-FC02-04ER54698, DE-SC0019352, and DE-FG02-97ER54415.

Presenters

  • Guiding Wang

    • University of California, Los Angeles

Authors

  • Guiding Wang

    • University of California, Los Angeles
  • Terry L Rhodes

    • University of California, Los Angeles
  • Quinn Pratt

    • University of California, Los Angeles
  • Rongjie Hong

    • University of California, Los Angeles
  • Julius Damba

    • University of California, Los Angeles (UCLA)
  • William A Peebles

    • University of California, Los Angeles
  • Max E Austin

    • University of Texas at Austin
    • University of Texas Austin
  • Kathreen E Thome

    • General Atomics - San Diego
    • General Atomics