Long radial coherence of electron temperature fluctuations in non-local transport in HL-2A plasmas

2023/11/09 by Shi, Zhongbing, Fang, Kairui, Li, Jingchun +13
#FOS: Physical sciences #Plasma Physics (physics.plasm-ph)

paper · doi:10.48550/arxiv.2311.05357

Abstract

The dynamics of long-wavelength (k_θ<1.4 \mathrm cm^-1), broadband (20-200 kHz) electron temperature fluctuations ( T_e/T_e) of plasmas in gas-puff experiments were observed for the first time in HL-2A tokamak. In a relative low density (n_e(0) ≃ 0.91 ∼ 1.20 ×10¹⁹/m³) scenario, after gas-puffing the core temperature increases and the edge temperature drops. On the contrary, temperature fluctuation drops at the core and increases at the edge. Analyses show the non-local emergence is accompanied with a long radial coherent length of turbulent fluctuations. While in a higher density (n_e(0) ≃ 1.83 ∼ 2.02 ×10¹⁹/m³) scenario, the phenomena were not observed. Furthermore, compelling evidence indicates that E × B shear serves as a substantial contributor to this extensive radial interaction. This finding offers a direct explanatory link to the intriguing core-heating phenomenon witnessed within the realm of non-local transport.

Related

• Fluctuation signatures of rotation reversals and non-local transport events in KSTAR L-mode plasmas
• Non-linear temperature oscillations in the plasma centre on Tore Supra and their interplay with MHD
• Density limit experiments and core-localized kinetic ballooning modes in HL-2A ohmic heating plasmas
• Evidence of Levy stable process in tokamak edge turbulence
• Effects of Turbulent Energy Exchange between Electrons and Ions on Global Temperature Profiles