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Abstract

N. Grzybicka¹, P. Chmielewski¹, P. Innocente²

¹ Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland

² Consorzio RFX, Padova, Italy

Reduction of the heat load on plasma-facing components is a critical challenge for future fusion reactors like DTT. One potential solution is to increase plasma radiation by introducing impurities into the plasma, thereby mitigating the power load in the Scrape-Off Layer (SOL).

This study presents a numerical analysis of the effects of seeded impurities on the radiation distribution and power load to the divertor plates in the high-field DTT reactor, configured in a single-null (SN) geometry. The simulations were conducted using the TECXY code, which models the transport of a multi-species plasma, including multiple ionization stages of impurities, in a two-dimensional poloidal plane. TECXY utilizes a classical set of multi-species plasma transport equations derived from Braginskii’s formulations to represent plasma behavior in the SOL.

The primary objective of this research is to compare the effectiveness of neon and argon impurities in reducing energy flux to the target plate in the DTT device, aiming to achieve significant mitigation with minimal impurity concentrations.

The findings demonstrate the impact of neon and argon seeding on the plasma boundary, specifically under conditions of constant electron density at the separatrix. Results indicate that argon seeding can achieve a reduction in electron temperature to as low as 3 eV at both the outer and inner divertor plates with lower impurity concentrations compared to neon seeding. The study highlights the complex interactions of neon and argon with the boundary plasma, with the most significant temperature and power reductions observed at higher upstream plasma densities. Additionally, the results emphasize that perpendicular diffusive transport plays a critical role in determining impurity radiation and, consequently, the plasma conditions at the divertor plates.