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Title: Linear properties of reversed shear Alfvén eigenmodes in the DIII-D tokamak

Journal Article · · Nuclear Fusion

Linear properties of the reverse shear Alfvén eigenmode (RSAE) in a well-diagnosed DIII-D tokamak experiment (discharge #142111) are studied in gyrokinetic particle simulations. Simulations find that a weakly damped RSAE exists due to toroidal coupling and other geometric effects. The mode is driven unstable by density gradients of fast ions from neutral beam injection. Various damping and driving mechanisms are identified and measured in the simulations. Accurate damping and growth rate calculation requires a non-perturbative, fully self-consistent simulation to calculate the true mode structure. The mode structure has no up–down symmetry mainly due to the radial symmetry breaking by the density gradients of the fast ions, as measured in the experiment by electron cyclotron emission imaging. The RSAE frequency up-sweeping and the mode transition from RSAE to TAE (toroidal Alfvén eigenmode) are in good agreement with the experimental results when the values of the minimum safety factor are scanned in gyrokinetic simulations.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Organization:
USDOE Office of Science (SC)
OSTI ID:
1564875
Journal Information:
Nuclear Fusion, Vol. 52, Issue 4; ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English

References (36)

Alfvén eigenmode and energetic particle research in JT-60U journal September 1998
MHD spectroscopy through detecting toroidal Alfvén eigenmodes and Alfvén wave cascades journal October 2001
New Interpretation of Alpha-Particle-Driven Instabilities in Deuterium-Tritium Experiments on the Tokamak Fusion Test Reactor journal September 2003
Active and fast particle driven Alfvén eigenmodes in Alcator C-Mod journal May 2005
Alfvén eigenmode observations on DIII-D via two-colour CO 2 interferometry journal August 2005
β suppression of Alfvén cascade modes in the National Spherical Torus Experiment journal October 2007
Theoretical Interpretation of Alfvén Cascades in Tokamaks with Nonmonotonic q Profiles journal October 2001
Theory of Alfvén eigenmodes in shear reversed plasmas journal September 2003
Finite pressure effects on reversed shear Alfvén eigenmodes journal September 2004
Plasma pressure effect on Alfvén cascade eigenmodes journal November 2005
Effects of pressure gradient on existence of Alfvén cascade modes in reversed shear tokamak plasmas journal May 2006
Reversed shear Alfvén eigenmodes associated with the ellipticity and triangularity Alfvén gaps journal July 2006
Interpretation of the finite pressure gradient effects in the reversed shear Alfvén eigenmode theory journal July 2006
Kinetic reversed-shear Alfvén eigenmodes journal September 2004
Existence of weakly damped kinetic Alfvén eigenmodes in reversed shear tokamak plasmas journal November 2008
Kinetic damping of Alfvén eigenmodes in general tokamak geometry journal July 2009
Turbulent Transport Reduction by Zonal Flows: Massively Parallel Simulations journal September 1998
Electromagnetic formulation of global gyrokinetic particle simulation in toroidal geometry journal December 2009
Gyrokinetic particle simulations of reversed shear Alfvén eigenmode excited by antenna and fast ions journal November 2010
Fast Ion Induced Shearing of 2D Alfvén Eigenmodes Measured by Electron Cyclotron Emission Imaging journal February 2011
Measurements and modeling of Alfvén eigenmode induced fast ion transport and loss in DIII-D and ASDEX Upgrade journal May 2011
Gyrokinetic particle simulation of beta-induced Alfvén eigenmode journal November 2010
Three‐dimensional hybrid gyrokinetic‐magnetohydrodynamics simulation journal March 1992
Hybrid magnetohydrodynamic-particle simulation of linear and nonlinear evolution of Alfvén modes in tokamaks journal September 1998
An extended hybrid magnetohydrodynamics gyrokinetic model for numerical simulation of shear Alfvén waves in burning plasmas journal May 2011
Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode journal May 1998
Continuum damping of high-mode-number toroidal Alfvén waves journal February 1992
Kinetic theory of toroidicity‐induced Alfvén eigenmodes journal September 1992
Reconstruction of current profile parameters and plasma shapes in tokamaks journal November 1985
Low-n shear Alfvén spectra in axisymmetric toroidal plasmas journal January 1986
A numerical study of the high‐ n shear Alfvén spectrum gap and the high‐ n gap mode journal November 1992
Kinetic theory of low-frequency Alfvén modes in tokamaks journal November 1996
Resonant damping of toroidicity-induced shear-Alfvén eigenmodes in tokamaks journal February 1992
A fluid–kinetic hybrid electron model for electromagnetic simulations journal May 2001
Canonical Hamiltonian guiding center variables journal April 1990
SLEPc: A scalable and flexible toolkit for the solution of eigenvalue problems journal September 2005

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