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Wall conditioning techniques applicable in the presence of the high toroidal magnetic field will be required for the operation of ITER for tritium removal, isotopic ratio control and recovery to normal operation after disruptions. Recently ion cyclotron wall conditioning (ICWC) experiments have been carried out on Tore Supra in order to assess the efficiency of this technique in ITER relevant conditions. The ICRF discharges were operated in He/H2 mixtures at the Tore Supra nominal field (3.8 T) and a RF frequency of 48 MHz, i.e. within the ITER operational space. RF pulses of 60 s (max.) were applied using a standard Tore Supra two-strap resonant double loop antenna in ICWC mode, operated either in π or 0-phasing with a noticeable improvement of the RF coupling in the latter case. In order to assess the efficiency of the technique for the control of isotopic ratio the wall was first preloaded using a D2 glow discharge. After 15 minutes of ICWC in He/H2 gas mixtures the isotopic ratio was altered from 4% to 50% at the price of an important H implantation into the walls. An overall analysis comparing plasma production and the conditioning efficiency as a function of discharge parameters is given. [ABSTRACT FROM AUTHOR]

ITER-like structures feature an intrinsic resilience to load variations, which is related to the symmetry of the currents in the two branches of the structure. It has been suggested that the effects of coupling between the array elements would significantly impair the load resilience of the structure. In this paper the effect of inter strap coupling and of however induced electrical array asymmetries on the structure load resilience are quantitatively examined. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A possible issue for the ITER Ion Cyclotron Heating and Current Drive system is related to the high electric field (2 kV/mm parallel to B0) at which the array is planned to operate, which may be associated to a low dielectric rigidity of the of the vessel “vacuum”. The combined effects are likely to set the upper limit to the RF power transfer efficiency to the plasma core. This paper addresses the problem of how to improve the power handling in the ITER IC launcher described in the ITER Final Design Report (FDR), to either operate at a significantly lower E-field in the torus vacuum or, alternatively, at a lower plasma coupling. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]