SOL width broadening by spreading of pedestal turbulence

Chu, Xu; Diamond, P. H.; Guo, Zhibin

doi:10.1088/1741-4326/ac4f9f

Title: SOL width broadening by spreading of pedestal turbulence

Journal Article · 04 April 2022 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ac4f9f · OSTI ID:1861491

^[1];

^[2]; Guo, Zhibin ^[3]

Univ. of Chinese Academy of Sciences, Beijing (China); Princeton Univ., NJ (United States); UC San Diego
Univ. of California San Diego, La Jolla, CA (United States)
Peking Univ., Beijing (China)

The pedestal turbulence intensity required to convert the thin, laminar H-mode scrape-off layer (SOL) to a broad turbulent SOL is calculated using the theory of turbulence spreading. A lower bound on the pedestal turbulence level to exceed the neoclassical heuristic drift (HD) width is derived. A reduced model of SOL turbulence spreading is used to determine the SOL width as a function of intensity flux from the pedestal to the SOL. The cross-over value for exceeding the HD model width is then calculated. We determine the pedestal turbulence levels—and the critical scalings thereof—required to achieve this level of broadening. Both drift wave and ballooning mode turbulence are considered. Here, a sensitivity analysis reveals that the key competition is that between spreading and linear E × B shear damping. The required pedestal turbulence levels scale with ρ/R.

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Research Organization:: Univ. of California, San Diego, CA (United States)

Sponsoring Organization:: USDOE

Grant/Contract Number:: FG02-04ER54738

OSTI ID:: 1861491

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 6 Vol. 62; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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