EUROPEAN NEGATIVE-ION BASED NEUTRAL BEAM DEVELOPMENTS

The European negative ion based neutral beam development programme consists presently of experiments on high energy electrostatic accelerators and high current D- sources, and of neutral beam physics and system design studies. At CEA-Cadarache the source test bed MANTIS started operation last June, and the 1 MV, 0.1 A, D- acceleration project SINGAP will be operational by the end of 1994. Additionally, negative ion source physics-oriented experiments will be conducted at Dublin City University. A Pagoda source, developed for the SINGAP experiment, recently produced more than 1 A D- beams and j(D-) of 10 mA cm(-2), with Cs seeding, at 0.6 Pa operating pressure. 1.3 A H- and 0.5 A D- beams have also been obtained without the use of Cs during the first experiments on MANTIS. Studies on neutral beam heating (NBH) for a next step machine have been conducted during 1993, mainly at JET and CEA-Cadarache. NBH physics studies based on the RLW model indicate that ignition on ITER-EDA should be reached with about 40 MW of 0.4-1 MeV D-0 beams. The outlines of an NBH system for ITER-EDA, based on SINGAP, have been studied.