A semi-analytic power balance model for low (L) to high (H) mode transition power threshold

Journal Article · Sun Jun 15 04:00:00 EDT 2014 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4882256· OSTI ID:22304193

Jhang, Hogun ^[1]; Kaw, P. K. ^[2]; Diamond, P. H. ^[1]; Nordman, H. ^[3]; Bourdelle, C. ^[4]; Loarte, A. ^[5]

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1. WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)
2. Institute for Plasma Research, Bhat Gandhinagar 2382 428 (India)
3. Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Göteborg (Sweden)
4. Euratom-CEA Association, CEA/DSM/DRFC, CEA Cadarache F-13108 Saint-Paul-Lez-Durance (France)
5. ITER Organization, Route de Vinon Sur Verdon, A. 13115 Saint Paul Lez Durance (France)

We present a semi-analytic model for low (L) to high (H) mode transition power threshold (P{sub th}). Two main assumptions are made in our study. First, high poloidal mode number drift resistive ballooning modes (high-m DRBM) are assumed to be the dominant turbulence driver in a narrow edge region near to last closed flux surface. Second, the pre-transition edge profile and turbulent diffusivity at the narrow edge region pertain to turbulent equipartition. An edge power balance relation is derived by calculating the dissipated power flux through both turbulent conduction and convection, and radiation in the edge region. P{sub th} is obtained by imposing the turbulence quench rule due to sheared E × B rotation. Evaluation of P{sub th} shows a good agreement with experimental results in existing machines. Increase of P{sub th} at low density (i.e., the existence of roll-over density in P{sub th} vs. density) is shown to originate from the longer scale length of the density profile than that of the temperature profile.

• OSTI ID: 22304193
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 21; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BALLOONING INSTABILITY
CONVECTION
EVALUATION
H-MODE PLASMA CONFINEMENT
MAGNETIC SURFACES
SHEAR
TURBULENCE