Toward a Large RF Ion Source for the ITER Neutral Beam Injector: Overview of the ELISE Test Facility and First Results

The ion source test facility extraction from a large ion source experiment (ELISE) has recently been built at Max Planck Institute for Plasma Physics (IPP) Garching (Germany) and has been operational since December 2012. ELISE is an important intermediate step in the R&D roadmap that the European domestic agency Fusion for Energy has defined for the International Thermonuclear Experimental Reactor (ITER) neutral beam injectors. This new test facility for a large radio frequency ion source builds up on the experience gained during many years of successful operation of smaller testbeds at IPP. The purpose of ELISE is to extract a negative ion beam, at ITER relevant parameters, using an ion source with the full width (1 m) and half the height of the ITER source. ELISE is designed to generate plasma for up to 1 h and extract a H- or D- beam at up to 60 kV. Available power supplies allow beam pulses of 10 s every 150-180 s. Although ELISE is designed to be as close as possible to the ITER source, technical solutions have been implemented that allow considerable experimental flexibility. Focus was put on easier diagnostic access and ease of maintenance. The results gained during the construction and operation of ELISE are delivering very important information to support the design and operation of the neutral beam test facility PRIMA to be built in Padua (Italy). This paper gives an overview of the project, presents experiences made during commissioning, and shows some basic results obtained so far.