Simulation of Turbulent Cross-Phase Angles and Effects on Energy Transport in Tokamaks*

Turbulent heat transport remains a complex and challenging subject in magnetically confined fusion power plants. Cross-phase angle measurements are crucial for understanding heat flux transport, but obtaining them experimentally across a wide range of plasma parameters is challenging. Numerical experiments allow for the study of cross-phase angles under standard experimental conditions and more extreme parameter spaces. The TGLF (Trapped Gyro-Landau-Fluid) model demonstrated highly accurate predictions of density and temperature profiles when benchmarked against tokamak discharges [1]. A comprehensive database of cross-phase angle measurements, covering various parameters relevant to several current tokamaks, is being developed using TGLF simulations. The objective is to identify parameter ranges where the amplitude of long wavelength electron temperature fluctuations and the cross-phase angle between density and temperature (n-T phase) track significant changes in turbulent heat flux. This information will help plan and interpret future experiments at ASDEX Upgrade using MIT CECE (Correlation Electron Cyclotron Emission) and n-T phase diagnostics [2,3] to study electron temperature fluctuations and the cross-phase angle between long wavelength density and temperature fluctuations.

 

[1] G.M. Staebler et al 2021 Nucl. Fusion 61 116007

[2] Bielajew et al, Phys. Plasmas 29, 052504 (2022)

[3] Yoo et al, RSI, in preparation