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Simulations of pedestal formation and ELM cycles

Authors :
J. McElhenny
Alexei Pankin
Christopher L. MacDonald
Arnold H. Kritz
Thawatchai Onjun
Glenn Bateman
Source :
Plasma Physics and Controlled Fusion. 48:A93-A99
Publication Year :
2006
Publisher :
IOP Publishing, 2006.

Abstract

Improved models are developed for integrated simulations of pedestal formation and edge localized mode (ELM) cycles at the edge of H-mode tokamak plasmas. The H-mode pedestal is formed in the simulations when flow shear and magnetic shear reduce the transport driven by drift modes at the edge of the plasma (Pankin A Y et al 2005 Plasma Phys. Control. Fusion 47 483). A large part of the flow shear is produced by the diamagnetic drift and the poloidal velocity, which is computed using a neoclassical model. Ion thermal transport is reduced to near the neoclassical level while electron thermal transport is reduced to the electron temperature gradient mode transport. A relatively large current density is driven in the pedestal by the bootstrap current. If the heating power is large enough, the pedestal growth is limited by ELM crashes, which are triggered by ideal MHD instabilities. Integrated simulations using these improved models are validated by comparing the simulation results with data for plasma profiles during the pedestal formation and with data for the ELM crash frequency. Simulations using the validated model are carried out for 31 Inernational Profile Database DIII-D and JET discharges.

Details

ISSN :
13616587 and 07413335
Volume :
48
Database :
OpenAIRE
Journal :
Plasma Physics and Controlled Fusion
Accession number :
edsair.doi...........169dbb34e50b3cf8fed6ed4c30f822b1
Full Text :
https://doi.org/10.1088/0741-3335/48/5a/s08