Neutral Beams for Fusion Research: Development and Application

Ion beam technology has advanced immensely during the past 15 years in connection with the application of neutral beam injection heating for fusion research. Ion sources have been scaled up along with necessary modifications, yielding currently a few megawatts of extraction power (e. g., 40 keV-60 A, 0.3-sec pulse). The entire neutral beam injection system has become a multidisciplinary technology including plasma physics, accelerator and beam physics, pumping technology, heat transfer, electrical engineering, and so on. Since the neutral beam injection heating of fusion plasmas has been proved the most viable means of increasing the plasma temperature to ignition, the future demand and requirements are rising with the size of fusion plasma devices. A brief review of the state of the art of neutral beam technology is presented and the direction of the future neutral beam field is discussed.