Dependence of divertor turbulence on plasma density and current in TCV

• DOI: 10.1088/1741-4326/ad8df1
• Publication Date: 2024-11-01T22:48:31Z
• Authors: C. Wüthrich; C. Theiler; D.S. Oliveira; Y. Wang; R. Ducker; G. Durr-Legoupil-...; B.P. Duval; D. Galassi; T. Golfinopolus; K. Lee; N. Offeddu; C.K. Tsui
• Keywords: scrape-off layer (SOL); filament; Nuclear and particle physics. Atomic energy. Radioactivity; turbulence; 0103 physical sciences; divertor; particle and heat fluxes; QC770-798; tokamak; 01 natural sciences

Abstract To reliably predict the distribution of heat and particle fluxes at target plates tokamaks, a comprehensive understanding turbulence throughout entire Scrape-Off-Layer (SOL) is imperative. This study examines divertor systematically across broad parameter range on TCV tokamak, including variations in magnetic field direction, plasma current <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>I</mml:mi> <mml:mi mathvariant="normal">p</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∈</mml:mo> <mml:mo stretchy="false">[</mml:mo> <mml:mn>140</mml:mn> <mml:mo>,</mml:mo> <mml:mn>320</mml:mn> stretchy="false">]</mml:mo> </mml:math> kA, edge safety factor <mml:mi>q</mml:mi> <mml:mn>95</mml:mn> <mml:mn>2.6</mml:mn> <mml:mn>4.7</mml:mn> Greenwald fraction <mml:mi>f</mml:mi> mathvariant="normal">G</mml:mi> <mml:mn>0.18</mml:mn> <mml:mn>0.6</mml:mn> . The X-point Gas Puff Imaging (GPI) system used to measure 2D filament properties inner outer region. fluctuation levels are found strongly increase with density (to 80% over most SOL) while remaining insensitive previously identified divertor-localized filaments (DLF), located bad curvature side leg, be common feature TCV, no observed PFR. DLFs present space both directions. However, they absent, or appear only closer target, for sufficiently large mathvariant="normal">Λ</mml:mi> <mml:mi>div</mml:mi> <mml:mo>≳</mml:mo> <mml:mn>10</mml:mn> <mml:mn>3.7</mml:mn> Across scans, some clear trends sizes velocities, fall-off lengths flux profiles target. provides important experimental insights turbulent transport also comparison self-consistent, simulations extrapolation future reactor conditions.