Search

To reach fusion conditions and control plasma configuration in ITER, a suitable combination of additional heating and current drive systems is necessary. Among them, two Neutral Beam Injectors (NBI) will provide a total of 33MW hydrogen/deuterium particles electrostatically accelerated to 1MeV; efficient gas-cell neutralisation at such beam energy requires negative ions, obtained by plasma-assisted caesium-catalysed surface conversion. The ion source plasma is generated by 8 inductively-coupled drivers (typical electron density of the order of 1018m-3 and electron temperature around 10-20eV at 0.3Pa filling pressure), expanding into a single 2m tall chamber after diffusing through a magnetic filter. By lowering the electron temperature and density, this creates the conditions for the existence of an ion-ion plasma in front of the apertures of the plasma electrode. The beam features depend on the parameters of this plasma. As ITER NBI requirements have never been simultaneously attained, a Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy), hosting two devices, which integrate the experience of several research groups worldwide. MITICA will represent the full-scale NBI prototype with 1MeV particle energy. SPIDER, with 100keV particle energy, started testing and optimising the full-scale ion source: extracted beam uniformity >90%, negative ion current density (for one hour) and beam optics (beam divergence

Recent research activities on ITER NBTF

This document gives an overall description of the activities performed by NBTF Team under WP2019.

This document concerns the proposal for a new diagnostic to be installed in the SPIDER ion source which would enable in-situ measurements of caesium adsorption rate. The motivations for this new diagnostic are the following: - Attempt to measure in-situ the desorption rate of various Cs-composites formed at surfaces inside the source - Verify the influence of a hydrogen atmosphere, and of a plasma discharge, on the chemical properties of the surfaces - Measure the amount of Cs deposited at a specific location inside the ion source - Verify the cumulative effects of many days of Cs evaporation and plasma discharges.

First operation of SPIDER and integrated power tests in MITICA.

To reach fusion conditions and to control the plasma configuration in ITER, the next step in thermonuclear fusion research, two heating and current-drive neutral beam injectors (NBIs) will supply 17MW each, by accelerating negative hydrogen or deuterium ions to 1MeV. The requirements of ITER NBIs (40A negative H or D ions for 1 hour) have never been simultaneously attained. So in the dedicated Neutral Beam Test Facility (NBTF) at Consorzio RFX (Italy) the performances of the ITER NBI (divergence

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 neutralization 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 (

Status of NBI for ITER and the related test facility