Speaker
Description
Recent dedicated experiments combined with a new modeling suite have advanced the crucial topic of core edge integration and power exhaust for fusion plasmas substantially. We report on experimental findings with reactor relevant seeding gases that establish a core edge integrated boundary solution. A new core-edge integrated modeling framework has been validated on these experiments and is available for extrapolation to future power plants.
Highly radiating plasmas in negative triangularity (NT) have been demonstrated through the use of reactor-relevant seeding gases, i.e., neon, argon, and krypton, as extrinsic impurities featuring simultaneously high performance (𝛽N >2), divertor heat flux reduction and intrinsically no ELMs [1]. We present a comprehensive core and divertor modeling which highlights the physics mechanisms leading to confinement improvements and simultaneous reduction of the divertor heat flux when mantle radiation is integrated with the NT configuration. Seeding with Kr and Ar lead to a reduction of the parallel heat flux at the divertor entrance compared to N and Ne effectively alleviating the power exhaust by reducing PSOL, which is one of the main advantages of working in NT configuration. Higher impurity compression for Ar and Kr is found compared to N and Ne. The high-Z impurities provide volumetric dissipation at lower concentrations at the separatrix up to ~90% in agreement with experimental estimates for fuel dilution. Thus, the same divertor conditions can be obtained with a reduced impurity concentration at the separatrix, which is important for integrated scenarios for exhaust. The results presented here support that there is a path to highly radiating, high performance NT plasmas with low PSOL and no ELMs which all enable a stable plasma material interface. Additionally, for future reactors, a NT shape naturally puts the divertor at large major radius, which means a larger wetted area for power loads is available with a great potential to improve core–edge integration, easing the divertor installation, remote access and maintenance technology.
Core-edge integrated simulations with the new developed SICAS framework (SOLPS-ITER Coupled to ASTRA-STRAHL) [2] provides self-consistent background plasma and impurity transport from the divertor to the core with good agreements with experimental data. This tool opens new possibilities in integrated modeling of fusion devices for the interpretation of current experiments, prediction for ITER as well as reactor design. Application of SICAS on other impurity seeding scenarios including closed divertors will be also discussed. By capturing the complex interplay between impurity transport, core confinement, and edge dissipation, SICAS provides a physics-based foundation for designing new integrated scenarios for exhaust.
[1] L Casali et al 2025 Plasma Phys. Control. Fusion 67 025007, [2] A. Welsh et al 2025 Nucl. Fusion 65 044002
Work supported by the U.S. Department of Energy, under Award(s) DE-SC0023100, NRC 31310022M0014, DE-FC0204ER54698, DE-SC0022270, DE-AC52-07NA27344, DEFG02-08ER54999.
| Speaker's title | Ms |
|---|---|
| Speaker's Affiliation | University of Tennesee-Knoxville |
| Member State or IGO | United States of America |
