Tempest Simulations of Collisionless Damping of the Geodesic-Acoustic Mode in Edge-Plasma Pedestals

Journal Article · Fri May 30 00:00:00 EDT 2008 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.100.215001· OSTI ID:21132467

Xu, X Q; Xiong, Z; Nevins, W M ^[1]; Gao, Z ^[2]; McKee, G R ^[3]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2. Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)
3. University of Wisconsin-Madison, Wisconsin 53706 (United States)

The fully nonlinear (full-f) four-dimensional TEMPEST gyrokinetic continuum code correctly produces the frequency and collisionless damping of geodesic-acoustic modes (GAMs) and zonal flow, with fully nonlinear Boltzmann electrons for the inverse aspect ratio {epsilon} scan and the tokamak safety factor q scan in homogeneous plasmas. TEMPEST simulations show that the GAMs exist in the edge pedestal for steep density and temperature gradients in the form of outgoing waves. The enhanced GAM damping may explain experimental beam emission spectroscopy measurements on the edge q scaling of the GAM amplitude.

• OSTI ID: 21132467
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 21 Vol. 100; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASPECT RATIO
COMPUTERIZED SIMULATION
ELECTRONS
EMISSION SPECTROSCOPY
FOUR-DIMENSIONAL CALCULATIONS
HOMOGENEOUS PLASMA
NONLINEAR PROBLEMS
TEMPERATURE GRADIENTS
TOKAMAK DEVICES