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Rotational shear effects on edge harmonic oscillations in DIII-D quiescent H-mode discharges

Journal Article · · Nuclear Fusion
 [1];  [2];  [2];  [2];  [3];  [2];  [2];  [4];  [5];  [6];  [2];  [4];  [5];  [2];  [4];  [4];  [6]
  1. General Atomics, San Diego, CA (United States); General Atomics
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of Texas, Austin, TX (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  5. Univ. of California, Davis, CA (United States)
  6. Univ. of Wisconsin, Madison, WI (United States)
+ Show Author Affiliations
In the quiescent H-mode (QH-mode) regime, edge harmonic oscillations (EHO) play an important role in avoiding transient edge localized mode (ELM) power fluxes by providing benign and continuous edge particle transport. A detailed theoretical, experimental and modeling comparison has been made of low-n (n ≤ 5) EHO in DIII-D QH-mode plasmas. The calculated linear eigenmode structure from the extended MHD code M3D-C1 matches closely the coherent EHO properties from external magnetics data and internal measurements using the ECE, BES, ECE-Imaging and microwave imaging reflectometer (MIR) diagnostics, as well as the kink/peeling mode properties found by the ideal MHD code ELITE. Numerical investigations indicate that the low-n EHO-like solutions from M3D-C1 are destabilized by the rotational shear while high-n modes are stabilized. This effect is independent of the rotation direction, suggesting that EHO can be destabilized in principle with rotation in either direction. Furthermore, the modeling results are consistent with observations of the EHO, support the proposed theory of the EHO as a rotational shear driven kink/peeling mode, and improve our understanding and confidence in creating and sustaining QH-mode in present and future devices.
Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-09CH11466; FC02-04ER54698; FG02-08ER54999; FG02-99ER54531; FG03-97ER54415
OSTI ID:
1351092
Alternate ID(s):
OSTI ID: 1258301
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 7 Vol. 56; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (4)

Summary of magnetic fusion plasma physics in 1st AAPPS-DPP meeting journal March 2018
Discovery of stationary operation of quiescent H-mode plasmas with net-zero neutral beam injection torque and high energy confinement on DIII-D journal March 2016
Physics of increased edge electron temperature and density turbulence during ELM-free QH-mode operation on DIII-D journal May 2018
Edge state selection by modulating E  ×  B shearing profile in toroidally confined plasmas journal May 2019

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Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DIII-D
EHO
ELM control
E×B shear
M3D-C1
QH-mode
rotational shear