Impurity transport driven by kinetic ballooning mode in the strong gradient pedestal of tokamak plasmas
Year: 2024
Type: article
Abstract: The impurity transport driven by kinetic ballooning mode (KBM) is theoretically studied in the DIII-D H-mode strong gradient pedestal plasmas. From the electromagnetic gyrokinetic equation, including the correction of the strong radial electric field, the dispersion relationship of KBM instability with non-trace impurity is firstly derived. Then, the turbulent impurity flux and ion heat flux, as well as the associated transport coefficients, are further calculated. Through the parametric dependence analysis of analytical results, it is found that dilution effects of light fully ionized impurities can reduce the drive of KBM by affecting the kinetic pressure gradient parameter α and diamagnetic effects, thus leading to a decrease in both the absolute value of the real frequency | ω r ′ | and the growth rate γ k ′ of KBM instability. Stronger dilution effects by increasing the impurity charge number Z or steepening the impurity density profile correspond to stronger effects. Moreover, the removal efficiency of light fully ionized impurities, quantified by the ratio between the impurity diffusivity and effective ion heat conductivity D z χ i eff ≈ 1 − b z + 4 ω Dz / ω r ′ 3 ( 1 + 1 / η i ) / 2 , increases with an increase of Z mainly due to the smaller impurity finite Larmor radius (FLR) effects reflected by
Source: Nuclear Fusion
Authors: Shanni Huang, Weixin Guo, Lu Wang
Institution: Huazhong University of Science and Technology
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,470
Awards: G703334396, G7217562219
OpenAlex ID: W4404592567