Microwave ion source with dual helical antenna for diagnostics neutral beam of ALBORZ tokamak

• Published in: Fusion engineering and design 2023-09, Vol.194, p.113835, Article 113835
• Main Authors: Sadeghi, Hossein, Amrollahi, Reza, Chakhmachi, Amir, Fazelpour, Samaneh
• Format: Article
• Language: English
• Subjects: Diagnostic; Divergence; Extraction system; Ion source; Neutral beam injection
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2023.113835

•A microwave ion source of the diagnostic neutral beam injection (DNBI) is designed and simulated for Alborz Tokamak.•The proposed new helical antenna in the microwave power source could help us to reach the plasma with higher density and stability in comparison to the common microwave ion sources.•Three-electrode accelerator system is designed and simulated for extraction of an ion beam with proper divergence angle. An efficient ion source of the diagnostic neutral beam injection (DNBI) is designed and simulated for Alborz Tokamak, based on the microwave plasma source. The diagnostic neutral beam is designed for use in some diagnostics system such as charge-exchange recombination spectroscopy (CXRS), Rutherford Scattering (RS), and Motional Stark Effect (MSE) of Alborz Tokamak. In this work, a new helical antenna is designed and simulated for a microwave plasma source, to reach a plasma density of order8.23×1017m−3. The microwave plasma source is employed by the high-efficient ion beam accelerator. In this simulation, three-electrodes in different potentials of 20 kV, −2 kV, and grounded respectively, are used as extraction system of the ion beam source. According to our design, nine apertures grids are considered for the accelerator system. The simulation results show that, the system can extract an ion beam with energy and current of 20 keV and 60 mA respectively. The extracted ion beam consists of nine beamlets, where the beam waist and the current of each of them are calculated about 3 mm and 6.5 mA, respectively. The results of this work indicate that the ion beam with minimum divergence angle of 32 mrad can be generated by the proposed ion beam source.