Year: 2025
Type: article
Abstract: The study on scaling the scrape-off layer (SOL) power width (λq ) is crucial for deepening the understanding of the SOL particle and heat transports. Due to the sparse distribution of the divertor Langmuir probes and the erosion of probe tips during the long-pulse high-performance operations on EAST, the estimation of SOL particle flux width (λjs , used to approximate λq ) from the measured ion saturation current density profile (js ) usually has relatively large uncertainty. This paper introduces a maximum a posteriori estimation method based on the Bayes’ theorem to reduce the fitting uncertainty for λjs (the fitting accuracy increases by 33% in terms of mean absolute error compared with the traditional ordinary least squares estimation). With the new estimation method and the FreeGS equilibrium code, the databases in Liu et al (2024 Nucl. Fusion 64 026002) are updated, which are further used to scale λjs . Compared with the old λjs scalings for the L-mode and H-mode databases in deuterium and helium plasmas, the updated λjs scalings show better regression quality with similar results. The deuterium and helium databases for L-mode and H-mode plasmas can be combined to get a unified scaling, λ j s [ mm ] = 1.35 ( L ¯ c [ m ] ) 1.07 f GW 0.46 β p − 0.38 ( P SOL / S LCFS [ MW ⋅ m − 2 ] ) 0.27 Z 0.23 , where L ¯ c is the averaged SOL connection length,
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G4912067268, G6439984674, G958774449
OpenAlex ID: W4409286406