Optimizing ion-cyclotron resonance frequency heating for ITER: dedicated JET experiments

In the past years, one of the focal points of the JET experimental programme was on ion-cyclotron resonance heating (ICRH) studies in view of the design and exploitation of the ICRH system being developed for ITER. In this brief review, some of the main achievements obtained in JET in this field during the last 5 years will be summarized. The results reported here include important aspects of a more engineering nature, such as (i) the appropriate design of the RF feeding circuits for optimal load resilient operation and (ii) the test of a compact high-power density antenna array, as well as RF physics oriented studies aiming at refining the numerical models used for predicting the performance of the ICRH system in ITER. The latter include (i) experiments designed for improving the modelling of the antenna coupling resistance under various plasma conditions and (ii) the assessment of the heating performance of ICRH scenarios to be used in the non-active operation phase of ITER.

[1]  F. C. Schüller,et al.  Status of the ITER IC H&CD System , 2009 .

[2]  D. Van Eester,et al.  Re-evaluation of ITER ion cyclotron operating scenarios , 2002 .

[3]  F. W. Perkins,et al.  Heating tokamaks via the ion-cyclotron and ion-ion hybrid resonances , 1977 .

[4]  Daniele Milanesio,et al.  ITER ICRF antenna analysis and optimization using the TOPICA code , 2010 .

[5]  J. Contributors,et al.  Operations of the External Conjugate‐T Matching System for the A2 ICRH Antennas at JET , 2009 .

[6]  F. Castejón,et al.  Calculation of the bootstrap current profile for the TJ-II stellarator , 2011, 1108.3721.

[7]  L. Horton,et al.  Bulk ion heating with ICRH in JET DT plasmas , 1999 .

[8]  I. Voitsekhovitch,et al.  Fast ions in mode conversion heating (3He)–H plasmas in JET , 2012 .

[9]  ITER relevant ICRF heating scenarios with large ion heating fraction , 2000 .

[10]  Jet Efda Contributors,et al.  Hybrid Couplers On The JET ICRF System: Commissioning And First Results on ELMs , 2007 .

[11]  F. W. Perkins,et al.  Radiofrequency sheaths and impurity generation by ICRF antennas , 1989 .

[12]  A. M. Messiaen,et al.  ICRH antenna coupling physics and optimum plasma edge density profile. Application to ITER , 2011 .

[13]  M. V. Hellermann,et al.  Visible charge exchange spectroscopy at JET , 1990 .

[14]  R. Neu,et al.  Interaction of ICRF fields with the plasma boundary in AUG and JET and guidelines for antenna optimization , 2009 .

[15]  Jean-Marie Noterdaeme,et al.  ELMs and sawteeth with ICRF heating on ASDEX Upgrade , 1999 .

[16]  J. Jacquinot,et al.  ICRF power-deposition profiles, heating and confinement of monster sawtooth and peaked-density profile discharges in JET , 1989 .

[17]  J. Contributors,et al.  Recent experiments on alternative dipole phasing with the JET A2 ICRF antennas , 2009 .

[18]  Richard Howell Goulding,et al.  Main design features and challenges of the ITER-like ICRF antenna for JET , 2005 .

[19]  Jet Efda Contributors,et al.  Overview on Experiments On ITER‐like Antenna On JET And ICRF Antenna Design For ITER , 2009 .

[20]  M. Brambilla,et al.  Influence of an evanescence layer in front of the antenna on the coupling efficiency of ion cyclotron waves , 2005 .

[21]  D. J. Campbell,et al.  Chapter 1: Overview and summary , 1999 .

[22]  M-L Mayoral,et al.  Controlling the profile of ion-cyclotron-resonant ions in JET with the wave-induced pinch effect. , 2002, Physical review letters.

[23]  Z. Vizvary,et al.  Heat loads on JET plasma facing components from ICRF and LH wave absorption in the SOL , 2011 .

[24]  W. Kerner,et al.  Plasma confinement in JET H?mode plasmas with H, D, DT and T isotopes , 1999 .

[25]  R. Felton,et al.  JET (3He)–D scenarios relying on RF heating: survey of selected recent experiments , 2009 .

[26]  Litwin.  Ion-cyclotron-frequency stabilization of internal kink mode and sawtooth oscillations in tokamaks. , 1988, Physical review letters.

[27]  Daniele Milanesio,et al.  Performance of the ITER ICRH system as expected from TOPICA and ANTITER II modelling , 2010 .

[28]  D. V. Eester,et al.  A variational principle for studying fast-wave mode conversion , 1998 .

[29]  Jet Efda Contributors,et al.  Improved break-in-slope analysis of the plasma energy response in tokamaks , 2008 .

[30]  E. Joffrin,et al.  Localized bulk electron heating with ICRF mode conversion in the JET tokamak , 2004 .

[31]  A. S. Kaye,et al.  Present and future JET ICRF antennae , 1994 .

[32]  W. Suttrop,et al.  Electron cyclotron emission radiometer upgrade on the Joint European Torus (JET) tokamak , 2004 .