Speaker
Description
Fast neutral beams produced by the acceleration and neutralization of negative hydrogen/deuterium ions will be injected into the experimental fusion reactor ITER for plasma heating. The prototype ITER neutral beam injector (SPIDER) was built at Consorzio RFX (Padua, Italy) and comprises eight driver volumes where radio-frequency (RF) power is inductively coupled to the plasma electrons and an expansion chamber with a magnetic filter (MF). Both experimental and numerical studies are being conducted with the long-term goal of comprehending the beam behavior and improving the source performance. This study outlines the fundamental physical and numerical principles of the fluid model for the prototype ion source. The model implemented in the numerical code FSFS2D provides a self-consistent two-dimensional description of the source, encompassing neutral gas dynamics, plasma chemistry, RF coupling in the source driver, and plasma transport via the magnetic filter. Separate continuity equations describe different particle species, and the energy equations govern electron and heavy species temperatures, while the Poisson equation describes plasma potential. The FSFS2D code has already been used to investigate the operational conditions of the SPIDER source, yielding reasonable agreement with the Langmuir probe data [1]. However, the simulations revealed important model shortcomings, such as reduced geometry limited only to one driver (out of 8 drivers) and the drift –diffusion approximation for calculating ion and neutral fluxes.
This paper focuses on the recent developments of the model devoted to the extension of the computational domain to two drivers and the replacement of the drift-diffusion model by the heavy species momentum equations. The results of simulations are compared to the experimental data from SPIDER device.
[1] R.Zagórski, et al., ”Numerical Simulations of the Plasma Parameters in the SPIDER Device,” IEEE Transactions on Plasma Science, vol. 52, no. 9, September 2024, , doi: 10.1109/TPS.2024.3397015
| Email address | roman.zagorski@ncbj.gov.pl |
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| Classification/Track | poster presentation |
| Visitor's Visa | no |
| Classification | Numerical simulations of sources, beams, space-charge, ion-optics |