18th Technical Meeting on Energetic Particles in Magnetic Confinement Systems

Neutral Beam Injection in a high-field stellarator

Not scheduled

20m

Control of Energetic Particle Confinement

Speaker

Celine Siyi Hue

Description

Neutral Beam Injection (NBI) is a critical method for plasma heating in fusion devices [5, 3, 1]. While NBI has been extensively studied in tokamaks, its implementation in high-field stellarator configurations presents unique challenges and opportunities. Plasmas in future stellarator power plants will be larger and denser than those in current stellarators, requiring NBI to operate at higher energies. At the same time, high field stellarators represent better confinement that implies a reduced losses of energetic particle.

This work focuses on optimizing NBI parameters to achieve sufficient core power deposition while minimizing energetic particle losses in a high-density, high-magnetic-field stellarator plasma. We investigate the interplay between injection parameters and plasma geometries to determine the optimal configuration for effective NBI heating and identify key factors that influence power deposition and energetic particle losses. These factors allow us to narrow down the parameter space for higher-order
optimization.

Our results suggest that beam energies around 300 keV may be required for high-field stellarators. Although these energies necessitate the use of negative-ion NBI systems [2, 6], they remain below the 500-1000keV threshold [4], beyond which engineering challenges become more significant. This study provides a foundation for further research, highlighting the limitations and trade-offs involved in extending NBI
technologies to reactor relevant stellarator.

References

[1] M.N.A. Beurskens et al. “Confinement in electron heated plasmas in Wendelstein 7-X and ASDEX Upgrade; the necessity to control turbulent transport”. In: Nuclear Fusion 62.1 (Dec. 2021), p. 016015. doi: 10 . 1088 / 1741 - 4326 / ac36f1. url: https : / / dx . doi . org / 10 . 1088 / 1741 -4326/ac36f1.

[2] U. Fantz et al. “Towards powerful negative ion beams at the test facility ELISE for the ITER and DEMO NBI systems”. In: Nuclear Fusion 57.11 (Aug. 2017), p. 116007. doi: 10.1088/1741-4326/aa778b. url: https://dx.doi.org/10.1088/1741-4326/aa778b.

[3] R. Hemsworth et al. “Status of the ITER heating neutral beam system”. In: Nuclear Fusion 49.4 (Apr. 2009), p. 045006. doi: 10.1088/0029-5515/49/4/045006. url: https://dx.doi.org/10.1088/0029-5515/49/4/045006.

[4] C. Hopf et al. “Neutral beam injection for fusion reactors: technological constraints versus functional requirements”. In: Nuclear Fusion 61.10 (Sept. 2021), p. 106032. doi: 10.1088/1741-4326/ac227a.
url: https://dx.doi.org/10.1088/1741-4326/ac227a.

[5] Madhavan M Menon. “Neutral beam heating applications and development”. In: Proceedings of the IEEE 69.8 (1981), pp. 1012–1029.

[6] G. Serianni et al. “First operation in SPIDER and the path to complete MITICA”. In: Review of Scientific Instruments 91.2 (Feb. 2020), p. 023510. doi: 10 . 1063 / 1 . 5133076. url: https://doi.org/10.1063/1.5133076.