Comparison of H-mode plasmas in JET-ILW and JET-C with and without nitrogen seeding

Tutkimustuotos: Lehtiartikkeli

Tutkijat

  • Aaro Järvinen
  • C. Giroud
  • P. Belo
  • S. Brezinsek
  • M. Beurskens
  • G. Corrigan
  • S. Devaux
  • P. Drewelow
  • D. Harting
  • A. Huber
  • S. Jachmich
  • K. Lawson
  • B. Lipschultz
  • G. Maddison
  • C. Maggi
  • C. Marchetto
  • S. Marsen
  • G. F. Matthews
  • A. G. Meigs
  • D. Moulton
  • B. Sieglin
  • M. F. Stamp
  • S. Wiesen

Organisaatiot

  • Association CCFE
  • Forschungszentrum Jülich
  • Max-Planck-Institut für Plasmaphysik
  • Association Belgium State
  • University of York
  • CNR-ENEA-EURATOM Association
  • Culham Centre for Fusion Energy

Kuvaus

In high confinement mode, highly shaped plasmas with edge localized modes in JET, and for heating power of 15-17 MW, the edge fluid code EDGE2D-EIRENE predicts transition to detachment assisted by nitrogen at the low field side (LFS) target when more than 50% of the power crossing the separatrix between ELMs is radiated in the divertor chamber, i.e. ∼4 MW. This is observed both in the ITER-like wall (JET-ILW) and in the carbon wall (JET-C) configurations and is consistent with experimental observations within their uncertainty. In these conditions, peak heat fluxes below 1 MW m-2 are measured at the LFS target and predicted for both wall configurations. When the JET-C configuration is replaced with the JET-ILW, a factor of two reduction in the divertor radiated power and 25-50% increase in the peak and total power deposited to the LFS divertor plate is predicted by EDGE2D-EIRENE for unseeded plasmas similar to experimental observations. At the detachment threshold, EDGE2D-EIRENE shows that nitrogen radiates more than 80% of the total divertor radiation in JET-ILW with beryllium contributing less than a few %. With JET-C, nitrogen radiates more than 70% with carbon providing less than 20% of the total radiation. Therefore, the lower intrinsic divertor radiation with JET-ILW is compensated by stronger nitrogen radiation contribution in simulations leading to detachment at similar total divertor radiation fractions. 20-100% higher deuterium molecular fraction in the divertor recycling fluxes is predicted with light JET-C materials when compared to heavy tungsten. EDGE2D-EIRENE simulations indicate that the stronger molecular contribution can reduce the divertor peak power deposition in high recycling conditions by 10-20% due to enhanced power dissipation by molecular interaction.

Yksityiskohdat

AlkuperäiskieliEnglanti
Artikkeli046012
Sivut1-19
JulkaisuNuclear Fusion
Vuosikerta56
Numero4
TilaJulkaistu - 16 maaliskuuta 2016
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

ID: 3304115