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Title: Heating and current drive requirements towards steady state operation in ITER

Steady state scenarios envisaged for ITER aim at optimizing the bootstrap current, while maintaining sufficient confinement and stability to provide the necessary fusion yield. Non-inductive scenarios will need to operate with Internal Transport Barriers (ITBs) in order to reach adequate fusion gain at typical currents of 9 MA. However, the large pressure gradients associated with ITBs in regions of weak or negative magnetic shear can be conducive to ideal MHD instabilities, reducing the no-wall limit. The E × B flow shear from toroidal plasma rotation is expected to be low in ITER, with a major role in the ITB dynamics being played by magnetic geometry. Combinations of H/CD sources that maintain weakly reversed magnetic shear profiles throughout the discharge are the focus of this work. Time-dependent transport simulations indicate that, with a trade-off of the EC equatorial and upper launcher, the formation and sustainment of quasi-steady state ITBs could be demonstrated in ITER with the baseline heating configuration. However, with proper constraints from peeling-ballooning theory on the pedestal width and height, the fusion gain and the maximum non-inductive current are below the ITER target. Upgrades of the heating and current drive system in ITER, like the use of Lower Hybridmore » current drive, could overcome these limitations, sustaining higher non-inductive current and confinement, more expanded ITBs which are ideal MHD stable.« less
Authors:
; ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. Princeton Plasma Physics Laboratory, Princeton, NJ 08543 (United States)
  2. MIT Plasma Science and Fusion Center, Cambridge, MA 02139 (United States)
  3. Oak Ridge National Laboratory, Oak Ridge, TN 37831-6169 (United States)
  4. CompX, Box 2672, Del Mar, CA 92014 (United States)
Publication Date:
OSTI Identifier:
22263875
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1580; Journal Issue: 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BOOTSTRAP CURRENT; CHARGED-PARTICLE TRANSPORT; ITER TOKAMAK; LOWER HYBRID CURRENT DRIVE; MAGNETIC FIELD CONFIGURATIONS; MAGNETOHYDRODYNAMICS; PLASMA; PRESSURE GRADIENTS; REVERSED SHEAR; TIME DEPENDENCE