来源:本站 作者: 发布时间:2019-05-05
报告题目：Simulations of divertor heat flux width using the BOUT++ transport
The BOUT++ fluid transport code has been developed with all cross-field drifts and sheath boundary conditions in the scrape-off-layer (SOL). The radial electric field (Er) is calculated by coupling a plasma transport model with the quasi-neutrality constraint in a vorticity equation. The steady state solutions of divertor heat flux width for both ions and electrons have been investigated for C-Mod and CFETR. The results have been compared with experimental measurements from C-Mod discharges using the IR camera, probe and surface thermocouple. The simulations identified two distinct regimes via a turbulence diffusivity scan: a drift dominant regime and a turbulence dominant regime. Goldston’s HD model yields a lower limit of the width in the drift dominant regime.
报告题目：Quasi-coherent mode simulation during inter-ELM period in HL-2A
The quasi-coherent mode (QCM) during inter-ELM period in HL-2A is studied with the six-field two-fluid module. Linear simulations show the peeling-ballooning mode (P-B mode) is stable, while the resistive ballooning mode(RBM) is unstable. From the linear resistivity scan, the growthrate match the theory of resistivity dependence, and thus, the linear result is verified. With an unstable resistive-ballooning mode from linear simulations, the nonlinear simulation has successfully reproduced the QCM inside the separatrix at the outboard mid-plane. The poloidal wave number and frequency from fluctuation analysis are almost the same as the experimental results. The phase shift between the electrical potential and the density fluctuation matches. The transport induced by the QCM dominants the particle transport in the simulation, and the ambient turbulence transport is small. This phenomenon can be found in similar experiments in other devices. Linear and nonlinear global profile scans show that the QCM is triggered by the density gradient, and stabilized by the temperature and temperature gradient. Based on these scans, the observed saturated density and density gradient profiles and the increasing temperature profile are explained. Using the “surface instability” model, based on ballooning mode, the predicted poloidal wave numbers match the similar experimental results in different devices.