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Fusion Reactor Materials
Published in C. K. Gupta, Materials in Nuclear Energy Applications, 1989
The injection of energetic particles into the plasma is a proven method of raising its temperature. In neutral beam injection heating, a stream of atoms of one or both of the reactant particles is injected into the plasma at very high velocity (a few thousand kilometers per second). The electrically neutral atoms collide with plasma ions, sharing their tenfold greater energy with them and becoming part of the plasma; indeed, this is a possible method for refueling the plasma. The enormous velocities required can only be produced by electrical acceleration of the particles to be injected, so they first have to be ionized, positively or negatively.
Magnetic Nuclear Fusion in Tokamaks
Published in Sergei Sharapov, Energetic Particles in Tokamak Plasmas, 2021
Apart from alpha particles, other types of energetic particles are often used in auxiliary heating of plasma to increase thermal plasma temperatures. Plasma heating with energetic ions produced from neutral beam injection (NBI) and/or ion cyclotron resonant heating (ICRH) are effective techniques widely used in present-day machines.
Conceptual Design of Control System for the Prototype RF-Driven Negative Ion Source at ASIPP
Published in Fusion Science and Technology, 2022
Y. Z. Zhao, C. D. Hu, Q. L. Cui, S. H. Song, Y. H. Xie, W. Liu
Neutral beam injection (NBI) is an effective method for fusion plasma heating and current driving.1,2 For the future China Fusion Engineering Test Reactor3,4 (CFETR), a NBI system is required in terms of a deuterium beam with beam energy of 1 MeV, beam power of 20 MW, and off-axis injection. At such a high beam energy level, a stable giant negative ion source is essential to attain an allowable neutralization efficiency. At present, two NBI systems have been constructed on the Experimental Advanced Superconducting Tokamak (EAST). Each EAST NBI with two hot cathode bucket ion sources can deliver 2- to 4-MW beam power with 50- to 80-keV beam energy in 10- to 100-s pulse lengths.5 Future fusion reactors (ITER, CFETR) are equipped with high-power and long-pulse NBI. When the beam energy is greater than 100 keV, the neutralization efficiency of the positive ion source decreases sharply, while the neutralization efficiency of the negative ion source remains at 60% to 70%. At the same time, compared with the hot cathode bucket ion source, the radio frequency (RF) ion source has a long lifetime and no tungsten contamination, which is better suited for long-pulse operation.6–8 Based on these two reasons, a NBI system based on a RF negative ion source has become the development trend of NBI technology.
Timing Synchronization System on RF-Driven Neutral Beam Injection System
Published in Fusion Science and Technology, 2022
Y. Li, C. D. Hu, Y. Z. Zhao, Q. L. Cui, X. L. Shu, Y. H. Xie, W. Liu
As one of the fusion plasma heating methods, neutral beam injection (NBI) is widely used in controlling magnetic confinement devices.1 Compared with the positive ion source, the negative ion source can still ensure high neutralization efficiency at high energy.2,3 Therefore, negative ion neutral beam injection (NNBI) will be used to realize a high-energy, long-pulse, and steady-state heating experiment.4,5 A radio-frequency (RF)–driven NNBI system mainly consists of a beam source system, a beamline and supporting system, a power supply system, a control system, and a diagnostic system, with beam energy up to 200 keV and beam pulse length up to 3600 s (Refs. 6, 7, and 8).
Study on Improvement of Injected Power for EAST-NBI
Published in Fusion Science and Technology, 2019
L. Z. Liang, J. L. Wei, S. Liu, Y. H. Xie, C. C. Jiang, W. Liu, J. J. Pan, Y. J. Xu, Z. M. Liu, Y. L. Xie, C. D. Hu, Y. Z. Zhao
The Experimental Advanced Superconducting Tokamak (EAST) research program aims to demonstrate steady-state, long-pulse, advanced high-performance H-mode operations with ITER-like configuration and heating. A substantial fraction of the plasma current is driven noninductively by current-drive power. Due to its high plasma heating efficiency and clear physical mechanisms, neutral beam injection is widely used in magnetic confinement fusion experimental devices.1–3 Two sets of neutral beam injectors (NBIs) were mounted for EAST in the 2014 and 2015 experiment campaigns,4–6 as shown in Fig. 1.