First operation in SPIDER and the path to complete MITICA.

The requirements of ITER neutral beam injectors (1 MeV, 40 A negative deuterium ion current for 1 h) have never been simultaneously attained; therefore, a dedicated Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Padova, Italy). The NBTF includes two experiments: SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), the full-scale prototype of the source of ITER injectors, with a 100 keV accelerator, to investigate and optimize the properties of the ion source; and MITICA, the full-scale prototype of the entire injector, devoted to the issues related to the accelerator, including voltage holding at low gas pressure. The present paper gives an account of the status of the procurements, of the timeline, and of the voltage holding tests and experiments for MITICA.

Overview of the negative ion based neutral beam injectors for ITER.

The ITER baseline foresees 2 Heating Neutral Beams (HNB's) based on 1 MeV 40 A D(-) negative ion accelerators, each capable of delivering 16.7 MW of deuterium atoms to the DT plasma, with an optional 3rd HNB injector foreseen as a possible upgrade. In addition, a dedicated diagnostic neutral beam will be injecting ≈22 A of H(0) at 100 keV as the probe beam for charge exchange recombination spectroscopy.

Concept development for the ITER equatorial port visible∕infrared wide angle viewing system.

The ITER equatorial port visible∕infrared wide angle viewing system concept is developed from the measurement requirements. The proposed solution situates 4 viewing systems in the equatorial ports 3, 9, 12, and 17 with 4 views each (looking at the upper target, the inner divertor, and tangentially left and right). This gives sufficient coverage.

Accurate polarization measurements with a dual photoelastic modulator.

Measurements of the polarization effects in multimirror experiments by using a dual photoelastic modulator are described. The effect of single and multiple mirrors in polarization measurements in two and three dimensions is discussed, and experimental results show how symmetrical placement of mirrors in three-dimensional geometry can eliminate changes in the polarization. Calibration procedures for a dual photoelastic modulator and potential error sources such as misalignment of analyzer, signal dc offset, and neglect of aperture size are presented.

Particle pinch with fully noninductive lower hybrid current drive in Tore Supra.

Recently, plasmas exceeding 4 min have been obtained with lower hybrid current drive (LHCD) in Tore Supra. These LHCD plasmas extend for over 80 times the resistive current diffusion time with zero loop voltage. Under such unique conditions the neoclassical particle pinch driven by the toroidal electric field vanishes.