Fusion Science and Technology / Volume 59 / Number 1T / January 2011 / Pages 128-131
A series of neutral beam injectors for plasma heating and diagnostics in modern magnetic fusion devices has been developed in the Budker Institute of Nuclear Physics. In ion sources of these injectors arc discharge or RF plasma boxes are used. Ion optical systems are optimized to produce ion beams with a low enough angular divergence. In order to provide beam focusing, the grids are formed as spherical segments. Such ballistically focused beams are further neutralized in a gas target and subsequently are used to heat or diagnose plasma. Obtained diagnostic neutral beams with precise focusing are widely used to measure plasma parameters by beam emission spectroscopy methods in tokamaks, stellarators, reversed field pinches and open traps. High power focused beams with small divergence are also necessary for heating of localized regions of plasma and in the devices with narrow access ports through which only small size, high power density beams can be transported. Transition to steady state operation regime of the injectors is discussed.