The realization of EU-DEMO will pose unprecedented challenges to the power exhaust system. Its plasma-facing components will have to cope with a steady-state load of about 450 MW (fusion + additional heating). It is expected that creating and controlling a proper radiating edge region will isotropically dissipate ~ 300 MW, with the remaining 150 MW flowing in the Scrape-off Layer towards the...
In the previous operation campaigns of W7-X stable, detached divertor plasmas were demonstrated [1,2,3,4]. These plasma also showed particle exhaust that enables high density steady-state operation and provided good impurity retention [5]. Hence, the initial results from W7-X operation show a potential of the island divertor concept used in W7-X for a reactor. Spectroscopic measurements and...
We aim to address the design and operation challenges of future tokamak fusion reactors by developing tools which combine data and simulations with automation and uncertainty quantification techniques. We will present recent progress towards this goal in model development, workflow automation, and plans to develop and validate these tools in collaboration with current and near-term...
Despite several theoretical approaches and few pioneering modelling results [1], the onset of the H-mode transport barrier around the separatrix remains a rather open issue. Understanding precisely the physics behind this enhancement on the confinement and being able to reproduce it in numerical simulations is still a major objective to analyse the performances of nowadays tokamaks and prepare...
Next steps machines such as ITER and DEMO will face unprecedented challenges related to heat exhaust. Impurity seeding will play a key role in spreading power on a sufficiently large surface area. Simulating impurity radiation in a given scenario requires i) radiation functions for the different ion stages and ii) the spatial distribution of the ion densities. The latter results from the...
The kinetic simulation method has been employed to study the plasma-wall interaction mechanism in various plasma conditions: multi-component plasmas, electronegative plasmas, and dusty plasmas. The negative species are considered to enter the sheath region from presheath side with truncated Maxwellian distribution, and the ions satisfy the Bohm and Bohm-Chodura conditions. The sheath...
Characterizing the scrape-off layer (SOL) transport of Wendelstein 7-X (W7-X) is essential to assess the efficiency of its unique exhaust concept, the island divertor configuration. Insights into the SOL dynamics in attached and detached conditions can be gained by the measurement of particle flows. Investigations of impurity flow velocities and line-radiation have been carried out with the...
Divertor detachment operation is of critical importance for future long pulse high power tokomaks, such as ITER and CFETR[1]. Partially detached divertor conditions are foreseen for ITER and DEMO. In conventional standard divertor (SD) operation, the effect of drifts on SD detachment is very strong, and the outer target heat loading is very higher than inner target with favorable-Bt...
In future fusion reactor, it is critical to achieve detachment for the divertor, in order to protect the targets and sustain the steady state operation. By introducing an additional X-point in the poloidal field, the snowflake divertor [1] has larger flux expansion and connection length compared with the single-null divertor. Thus, the snowflake divertor is expected to promote the detachment,...
It is essential to control the plasma flow onto the divertor targets to avoid unacceptable heat load and erosion, and the contamination due to the sputtered impurities to avoid the degradation of the performance of confined plasma. Thus, comprehensive understanding of the plasma and impurity transport in the scrape-off layer (SOL) is necessary for exploring the divertor solution for the future...
The SPARC tokamak is a compact, high-field short pulse device (B0 = 12.2 T, R0 = 1.85 m, τflattop = 10 s) that plans to begin operations in mid-2025. It will execute a series of mission-driven campaigns to close science gaps to inform the design of the ARC fusion pilot plant to begin operation in the early 2030’s. Accomplishing this requires a versatile plasma diagnostic set for use in...
