Transport analysis of NBI heating H-mode experiment on HL-2 A with integrated modeling

Abstract

The physical process of tokamak plasma spans a large space-time scale, and the main physical processes differ widely in different spatial regions (such as core, pedestal, scraping-off layer, divertor region), so it is necessary to adopt the integrated modeling method to analyze the physical problems on a global multi-space-time scale. In order to study in depth the transport and confinement during the steady-state or ramp-up of the tokamak discharging experiment, it is necessary to use a variety of physical programs to carry out integrated simulation research and physical analysis. Based on the OMFIT platform, in this paper the integrated simulation verification and analysis of the shot #37012 are conducted, which is a high-<inline-formula><tex-math id="M1">\begin{document}$\beta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20211941_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20211941_M1.png"/></alternatives></inline-formula> discharge experiment on HL-2A device and verifies the reliability and applicability of those programs. In this process, the experimental parameters are checked and supplemented by selecting appropriate models. The simulation results after evolution are consistent with the experimental results. On this basis, we use the TGLF model to analyze the linear electrostatic drift wave instability in the core region. The reason for the improvement of the H-mode confinement by NBI off-axis heating is that the ETG instability in the NBI power deposition region is suppressed. The transport is dominated by ITG instability in the internal transport barrier (ITB), and the transport is reduced to the level of neoclassical transport.