FT/P2-30 Focused Neutral Beam With Low Chaotic Divergence For Plasma Heating And Diagnostics in Magnetic Fusion Devices

A series of neutral beam injectors has been developed in the Budker Institute of Nuclear Physics, Novosibirsk for plasma heating and diagnostics in modern fusion devices. Ion optical system of these injectors is optimized to produce ion beams with low angular divergence. In order to provide beam focusing, the grids are formed as spherical segments. Such geometrically focused beams are neutralized in a gas target and subsequently are used to heat or diagnose plasma. For diagnostic purposes these beams are advantageous when high spatial resolution is necessary. In many cases such focused beam with small divergence are also necessary for plasma heating in the machines with narrow ports through which only small size, high power density beams can be transported.