Nuclear Materials and Energy (Oct 2022)

The radiated power limit in impurity seeded JET-ILW plasmas

  • A. Huber,
  • M. Wischmeier,
  • S. Wiesen,
  • M. Bernert,
  • A.V. Chankin,
  • S. Aleiferis,
  • S. Brezinsek,
  • V. Huber,
  • G. Sergienko,
  • C. Giroud,
  • M. Groth,
  • S. Jachmich,
  • Ch. Linsmeier,
  • B. Lomanowski,
  • C. Lowry,
  • G.F. Matthews,
  • A.G. Meigs,
  • Ph. Mertens,
  • S. Silburn,
  • G. Telesca

Journal volume & issue
Vol. 33
p. 101299

Abstract

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The total radiated fraction is examined in high density H-mode plasmas (Greenwald fraction of about 85 %) in JET by the variation of the auxiliary heating power of Pheat = 14 MW-29 MW. An achieved radiation fraction of about 75 % at most has been observed in JET-ILW, which is less than the highest achievable (≈90 %) fraction in JET-C during the high radiative power scenarios with N2 seeding. It is shown that the maximal achievable total radiation fraction averaged over ELM cycles has a strong dependence on the radiation efficiency of the ELM energy, θrad: γrad,totalmax=1-fELM×ΔWELMPheat1-θrad. About 50 % and 16 % of the ELM induced diamagnetic energy drop (ΔWELM) radiates during the ELM in JET-C and JET-ILW, respectively, which corresponds to the maximum total radiated powers of γrad,JET-Cmax=0.87 and γrad,JET-ILWmax=0.77. These values of the maximum of the radiative power fractions are in good agreement with γradmax experimentally observed in JET-C (90 %) and JET-ILW (75 %).

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