Physics Analysis to Optimize the Performance of the ITER ECW System (Contributo in atti di convegno)

Type
Label
  • Physics Analysis to Optimize the Performance of the ITER ECW System (Contributo in atti di convegno) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Ramponi G., Farina D., Henderson M. A., Poli E., Saibene G., Sauter O., Zohm H., Zucca C. (2007)
    Physics Analysis to Optimize the Performance of the ITER ECW System
    in Proc. 4th IAEA Technical Meeting on "ECRH Physics and Technology for ITER", Vienna, 6-8 June 2007
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Ramponi G., Farina D., Henderson M. A., Poli E., Saibene G., Sauter O., Zohm H., Zucca C. (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni
  • Pagina 26 del libro degli abstracts di cui al link riportato sopra (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url
  • http://www-naweb.iaea.org/napc/physics/meetings/4ECRH/BoA_ECRH_final%2030.05%20.pdf (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Istituto di Fisica del Plasma, CNR Milano. (literal)
Titolo
  • Physics Analysis to Optimize the Performance of the ITER ECW System (literal)
Abstract
  • The ITER ECW system consists of up to 24, 170 GHz gyrotrons, 1 to 2 MW each, connected to one launcher situated in one equatorial port (EL) and four launchers in the upper ports (UL), for a nominal injected power of 20MW. The two launchers systems, designed to inject mm-waves at various locations in the plasma, have different current drive characteristics: beams launched from the EL, having toroidal steering, give broad jCD profiles and higher total driven current, good for central deposition and current profile control, while the UL, where the beams are steered in the poloidal direction, gives narrow jCD profiles, good control of MHD activity such as NTM and sawteeth. Up to the end of 2005 the main goal of the physics analysis has been to evaluate the performance of the UL both in terms of the required steering range and of the figure of merit for Neoclassical Tearing Modes (NTMs) stabilization (?NTM=JCD/Jbs), for (2,1) and (3,2) modes for three reference ITER scenarios and for two launcher designs, the Front Steering (FS) and the Remote Steering (RS). Since the FS offers appreciable reserve in ?NTM, a new variant of the UL has been designed that improves the capabilities of the system with respect to sawteeth stabilization, by adopting different deposition ranges for upper and lower mirrors while still maintaining acceptable ?NTM over the full range. A possible synergy between the UL and EL has been pointed out, with the ultimate goal of providing an enhanced physics program in ITER. In this work it is shown that, by adding to present design of the EL the possibility to drive counter-current in addition to the existing co-current capability as well as modifying the poloidal tilt angle for the top and bottom steering mirrors, the flexibility of the system is increased and heating and current drive may be decoupled, increasing the capability for the control of the discharge and enhancing the operational domain. The possibility to avoid sawteeth by raising the q profile above q=1 in a variant of Scenario 2 and the large flexibility in controlling q0 in the advanced Scenario 4 are shown. For the UL, the performance for NTM and sawteeth control by injecting the R.F. beams from a lower location are compared with that achieved with the present port location, both at nominal and at reduced magnetic field. *) This work has been carried out under EFDA Technology Task TW6-TPHE-ECHULA (literal)
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