Year: 2025
Type: article
Abstract: We investigate the turbulence statistics associated with low-to-high confinement (L-H) transitions and externally applied resonant magnetic perturbations (RMPs) in KSTAR. Time-series fluctuations of electron density n e , electron temperature T e , and the time derivative of the poloidal magnetic field d B θ / d t (Mirnov coils) are analysed using information-geometric measures (information rate Γ and information length L = ∫ Γ d t ), together with kurtosis κ and variance σ 2. In low-density upper single-null plasmas ( n e ∼ 1.2 × 10 19 m − 3 ), a ∼ 80 kHz magnetic mode coupling n e , T e , and d B θ / d t emerges prior to the L-H transition and persists into the edge-localised modes H-mode. Edge-localised RMPs (ERMPs) suppress this coherent mode but enhance intermittency, producing frequent bursts that abruptly reshape the time-dependent probability density functions (PDFs) and generate large spikes in Γ (with smaller changes in κ), signalling ERMP-driven departures from quasi-stationarity. The impact of ERMPs on background fluctuation levels depends on density, radial location, and the fluctuating variable itself ( n ~ , T ~ , B ˙ θ
Authors: Eun-jin Kim, Huiwon Chung, Minjun Choi, Yoonji Lee, Seongjun Han, Gyungjin Choi, Jong Gyu Park, Seong Moo Yang, Yong-Su Na
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1368267253, G3812690899
OpenAlex ID: W4414272490