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Title: EC assisted start-up experiments reproduction in FTU and AUG for simulations of the ITER case

The breakdown and plasma start-up in ITER are well known issues studied in the last few years in many tokamaks with the aid of calculation based on simplified modeling. The thickness of ITER metallic wall and the voltage limits of the Central Solenoid Power Supply strongly limit the maximum toroidal electric field achievable (0.3 V/m), well below the level used in the present generation of tokamaks. In order to have a safe and robust breakdown, the use of Electron Cyclotron Power to assist plasma formation and current rump up has been foreseen. This has raised attention on plasma formation phase in presence of EC wave, especially in order to predict the required power for a robust breakdown in ITER. Few detailed theory studies have been performed up to nowadays, due to the complexity of the problems. A simplified approach, extended from that proposed in ref[1] has been developed including a impurity multispecies distribution and an EC wave propagation and absorption based on GRAY code. This integrated model (BK0D) has been benchmarked on ohmic and EC assisted experiments on FTU and AUG, finding the key aspects for a good reproduction of data. On the basis of this, the simulation has beenmore » devoted to understand the best configuration for ITER case. The dependency of impurity distribution content and neutral gas pressure limits has been considered. As results of the analysis a reasonable amount of power (1 - 2 MW) seems to be enough to extend in a significant way the breakdown and current start up capability of ITER. The work reports the FTU data reproduction and the ITER case simulations.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Associazione EURATOM-ENEA sulla Fusione, IFP-CNR, Via R. Cozzi 53, 20125 Milano (Italy)
  2. F4E C/Josep Pla2, Torres Diagonal Litoral - Building 83 08019 Barcelona (Spain)
  3. CREATE via Claudio 21, 80125 Napoli (Italy)
  4. Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching bei München (Germany)
  5. Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Roma) (Italy)
Publication Date:
OSTI Identifier:
22263895
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; ABSORPTION; BREAKDOWN; DISTRIBUTION; ELECTRIC FIELDS; ELECTRIC POTENTIAL; IMPURITIES; ITER TOKAMAK; PLASMA; REPRODUCTION; SIMULATION; SOLENOIDS; START-UP; WAVE PROPAGATION