Modeling of divertor power footprint widths on EAST by SOLPS5.0/B2.5-Eirene

The edge plasma code package SOLPS5.0 is employed to simulate the divertor power footprint widths of the experimental advanced superconducting tokamak (EAST) L-mode and ELM-free H-mode plasmas. The divertor power footprint widths, which consist of the scrape-off layer (SOL) width λ _q and heat spreading S, are important physical parameters for edge plasmas. In this work, a plasma current scan is implemented in the simulation to obtain the dependence of the divertor power footprint width on the plasma current I _p. Strong inverse scaling of the SOL width with I _p has been achieved for both L-mode and H-mode plasmas in the forms of ${\lambda }_{q,L\text{-}\text{mode}}=4.98\times I_p^{-0.68}$ and ${\lambda }_{q,H\text{-}\text{mode}}=1.86\times I_p^{-1.08}.$ Similar trends have also been demonstrated in the study of heat spreading with $S_{L\text{-}\text{mode}}=1.95\times I_p^{-0.542}$ and $S_{H\text{-}\text{mode}}=0.756\times I_p^{-0.872}.$ In addition, studies on divertor peak heat load and the magnetic flux expansion factor show that both of them are proportional to plasma current. The simulation work here can act as a way to explore the power footprint widths of future tokamak fusion devices such as ITER and the China Fusion Engineering Test Reactor (CFETR). (paper)