Recent progress in development of neutral beams for fusion studies

A number of neutral beams with ballistic focusing were developed in several recent years for fusion studies in the Budker Insitute. Diagnostic neutral beam injectors for large stellarator W-7X and tokamak T-15 were produced and tested. A high power, relatively low energy neutral beam injector was developed to upgrade the neutral beam system of the gas dynamic trap device and C2-U/W experiments. This injector produces a proton beam with the particle energy of 15 keV, ion current of up to 175 A, and pulse duration up to 30 ms. For tokamaks Globus-M and TCV heating injectors of focused neutral beams with power ∼1 MW and duration ∼1 s were elaborated and produced. Future development of diagnostic and heating neutral beam injectors is discussed in the paper.