1. Achievement of high power and long pulse negative ion beam acceleration for JT-60SA NBI.
- Author
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Hiratsuka, J., Kashiwagi, M., Ichikawa, M., Umeda, N., Saquilayan, G. Q., Tobari, H., Watanabe, K., Kojima, A., and Yoshida, M.
- Subjects
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ANIONS , *ION beams , *ION accelerators , *ELECTROSTATIC accelerators , *ACCELERATION (Mechanics) , *PLASMA beam injection heating - Abstract
Long pulse acceleration of hydrogen negative ion beams with the power density over 70 MW/m2 and the pulse length over 100 s has been demonstrated for the first time by using a multi-aperture 3-stage accelerator. Such long pulse acceleration was achieved by integrating the design of beam optics and voltage holding capability to meet the requirements of JT-60SA. By using the newly designed accelerator for JT-60SA, voltage holding at 500 kV with beam acceleration was stably sustained even after 5 g of cesium was seeded, and heat load on each acceleration grid was reduced below the allowable level for long pulse, less than 5% of total acceleration power. As a result, 500 keV, 154 A/m2 for 118 s beam acceleration was achieved, which satisfies the requirement of the negative ion source for JT-60SA. This pulse length of such high-power density beams is longest in the world. In addition, the result contributes to the long pulse acceleration of multi-stage electrostatic accelerators, such as 1 MeV negative ion accelerator for ITER. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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