Speaker
Description
H-mode with ELMs (Edge Localized modes) plasma regime is considered to be a preferable scenario in the future fusion devices as ITER. Heat loads on divertor during ELMs especially the type I ELMs is an important issue [1-2]. An infrared (IR)/visible endoscope system was built on the Experimental Advanced Superconducting Tokamak (EAST) in 2014. Based on the IR data in the experiment of 2014, the heat fluxes on the lower outer divertor were calculated with a code named DFLUX developed by ASIPP, aimed to provide reference for the H-mode operation of EAST [3]. Heat fluxes on lower outer divertor during ELMs without neutral beam injection (NBI) and with different NBI power were calculated and compared. The analyzed discharges were lower single null (LSN) divertor configuration discharges. In the case with lower-hybrid wave current drive (LHCD) only (Ip ~ 400kA, PLHCD ~2MW), ELM-free occurred after L-H transition accompanied by the increasing electron density (ne). The peak heat fluxes on lower outer divertor during ELM-free were not more than 1MW/m2. Then ELMs occurred and ne began to reduce and eventually lead to H-L transition. The peak heat flux on lower outer divertor during ELMs was not more than 2MW/m2 mostly. In the case LHCD combined with NBI (Ip ~ 300kA, PLHCD+PNBI ~2MW), type I ELMs occurred after L-H transition and ne was still increasing. The peak heat flux on lower outer divertor during ELMs was more than 3MW/m2 or even 5MW/m2 and ELMs disappeared when NBI was turned off mostly. By comparing the heat flux profile of divertor target versus radius in ELM, it may be because that the heat flux profile in ELM with NBI was narrow. The peak and averaged heat flux on lower outer divertor during ELMs did not increase with the increase of PNBI. The work of this paper will provide reference for H-mode discharge with NBI of EAST.
| Eligible for student paper award? | Yes |
|---|