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Contribution Oral

Beam lines and facilities

Start of SPIDER operation towards ITER Neutral Beams

Speakers

  • Prof. Giuseppe CHITARIN

Primary authors

Co-authors

Content

To reach fusion conditions and control plasma configuration in ITER, the next step towards establishing nuclear fusion as viable energy source, suitable combination of additional heating and current drive systems is necessary. Among them, two Neutral Beam Injectors (NBI) will provide 33MW hydrogen/deuterium particles electrostatically accelerated to 1MeV; efficient gas-cell neutralisation at such beam energy requires negative ions, obtained by caesium-catalysed surface conversion of hydrogen/deuterium atoms in the ion source. ITER NBI requirements have never been simultaneously attained; so a Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy). Experiments will verify continuous NBI operation for one hour, under stringent requirements for beam divergence (<7mrad) and aiming (within 2mrad). To study and optimise NBI performances, the NBTF includes two experiments: MITICA, full-scale NBI prototype with 1MeV particle energy; SPIDER, with 100keV particle energy and 40A current, aiming at testing and optimising the full-scale ion source. SPIDER will focus on source uniformity (~1.5m2 beam area), negative ion current density and beam optics. The SPIDER experiment, just entered into operation, will profit both from strong numerical activities, simulating experimental scenarios, and refined diagnostic instruments, providing thorough plasma and beam characterisation.

The contribution is dedicated to the activities carried out at the NBTF regarding SPIDER and the supplementary small facilities specifically devoted to coupling of radiofrequency to plasma, voltage holding with magnetic fields, distribution of caesium emitted from the evaporators. SPIDER has just entered into operation: the experimentatal plan will be described as well as the first experiments, including the preliminary characterisation of the beam source features at low RF power.

This work was set up in collaboration and financial support of F4E.