skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Modeling of 3D magnetic equilibrium effects on edge turbulence stability during RMP ELM suppression in tokamaks

Journal Article · · Nuclear Fusion
ORCiD logo [1];  [1];  [1];  [2];  [1];  [3];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. General Atomics, San Diego, CA (United States)
+ Show Author Affiliations

Some recent experimental observations have found turbulent fluctuation structures that are non-axisymmetric in a tokamak with applied 3D fields. Here, two fluid resistive effects are shown to produce changes relevant to turbulent transport in the modeled 3D magnetohydrodynamic (MHD) equilibrium of tokamak pedestals with these 3D fields applied. Ideal MHD models are insufficient to reproduce the relevant effects. By calculating the ideal 3D equilibrium using the VMEC code, the geometric shaping parameters that determine linear turbulence stability, including the normal curvature and local magnetic shear, are shown to be only weakly modified by applied 3D fields in the DIII-D tokamak. These ideal MHD effects are therefore not sufficient to explain the observed changes to fluctuations and transport. Using the M3D-C1 code to model the 3D equilibrium, density is shown to be redistributed on flux surfaces in the pedestal when resistive two fluid effects are included, while islands are screened by rotation in this region. Furthermore, the redistribution of density results in density and pressure gradient scale lengths that vary within pedestal flux surfaces between different helically localized flux tubes. This would produce different drive terms for trapped electron mode and kinetic ballooning mode turbulence, the latter of which is expected to be the limiting factor for pedestal pressure gradients in DIII-D.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Grant/Contract Number:
AC05-00OR22725; AC02-09CH11466; FC02-04ER54698
OSTI ID:
1376604
Alternate ID(s):
OSTI ID: 1374600
Journal Information:
Nuclear Fusion, Vol. 57, Issue 11; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

References (21)

Edge stability and transport control with resonant magnetic perturbations in collisionless tokamak plasmas journal May 2006
The EPED pedestal model and edge localized mode-suppressed regimes: Studies of quiescent H-mode and development of a model for edge localized mode suppression via resonant magnetic perturbations journal May 2012
Decoupled recovery of energy and momentum with correction of n   =  2 error fields journal July 2015
Drift waves and transport journal April 1999
Increase of turbulence and transport with resonant magnetic perturbations in ELM-suppressed plasmas on DIII-D journal September 2013
Three-dimensional free boundary calculations using a spectral Green's function method journal December 1986
Experimental tests of linear and nonlinear three-dimensional equilibrium models in DIII-D journal July 2015
Calculations of two-fluid linear response to non-axisymmetric fields in tokamaks journal May 2012
Evidence of Toroidally Localized Turbulence with Applied 3D Fields in the DIII-D Tokamak journal September 2016
Connection between plasma response and resonant magnetic perturbation (RMP) edge localized mode (ELM) suppression in DIII-D journal September 2015
Geometry dependence of stellarator turbulence journal November 2009
Local Stability Analysis of Three-dimensional Magnetically Confined Plasmas journal January 1997
Visualization of magnetically confined plasmas journal July 1999
Effects of E×B velocity shear and magnetic shear on turbulence and transport in magnetic confinement devices journal May 1997
Dynamics of Zonal Flows in Helical Systems journal March 2005
Effect of resonant magnetic perturbations on microturbulence in DIII-D pedestal journal October 2016
Local three-dimensional magnetostatic equilibria journal January 2000
Verification of the ideal magnetohydrodynamic response at rational surfaces in the VMEC code journal January 2016
Role of singular layers in the plasma response to resonant magnetic perturbations journal July 2012
Development and validation of a predictive model for the pedestal height journal May 2009
Magnetic-flutter-induced pedestal plasma transport journal September 2013

Cited By (4)

Helical variation of density profiles and fluctuations in the tokamak pedestal with applied 3D fields and implications for confinement journal May 2018
Predict-first experimental analysis using automated and integrated magnetohydrodynamic modeling journal May 2018
Effects of the applied magnetic fields with various toroidal phase differences on the neoclassical toroidal viscosity in JT-60SA journal October 2018
L – H transition trigger physics in ITER-similar plasmas with applied n   =  3 magnetic perturbations journal September 2019

Similar Records

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
RMP
equilibrium
turbulence