ECRH at high heating power density in FTU tokamak

S. Cirant, A. Airoldi, L. Bertalot, A. Bruschi, G. Bracco, P. Buratti, G. Cenacchi, B. Esposito, G. Granucci, H. Kroegler, E. Lazzaro, S. Nowak, G. Ramponi, C. Sozzi, O. Tudisco, M. Zerbini

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Abstract

Plasma absorption at the fundamental EC resonance of e.m. waves at 140 GHz, 0.8 MW, Ordinary mode, provides in the FTU tokamak a localized (minimum δr ≃ 2.5 cm) and intense (up to ≃ 100 MW/m3) heat source for the electrons. It is shown that at high density (≃ 1020mγ--3) ions are heated (ΔTi/Ti= 0.25) by collisional e - i energy transfer and assuming ion thermal diffusivity about three times larger (at most) than predictions in order to account for the observed Ti. Off-center localization (rabs/a ≃ 0.2) of the ECRH heat source changes the electron temperature (and current density) profile in a way to fully stabilize sawteeth. On-axis absorption accelerates the sawtooth crash repetition rate if Pecrh≤ Poh, but with Pecrh> Pohthe sawtooth period is increased. A critical shear model for the sawtooth crash repetition rate is shown to be in agreement with its experimental dependence on resonance position and heating power. In discharges characterized by a flat temperature profile in the ohmic phase, ECRH may de-stabilize tearing modes of different order, with a strong degradation of core energy confinement. © 2001 Published by Elsevier Science B.V.
Original languageEnglish
Pages (from-to)301 - 308
Number of pages8
JournalFusion Engineering and Design
Volume53
Issue number1-4
DOIs
Publication statusPublished - Jan 2001
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Materials Science(all)
  • Nuclear Energy and Engineering
  • Mechanical Engineering

Cite this

Cirant, S., Airoldi, A., Bertalot, L., Bruschi, A., Bracco, G., Buratti, P., ... Zerbini, M. (2001). ECRH at high heating power density in FTU tokamak. Fusion Engineering and Design, 53(1-4), 301 - 308. https://doi.org/10.1016/S0920-3796(00)00509-3