The experiment and simulation of the divertor power asymmetry in EAST

Divertor asymmetry and scrape-off layer (SOL) flow have been systematically investigated in the Experimental Advanced Superconducting Tokamak (EAST), with respect to toroidal field direction, divertor configuration, power injection methods and heating power. The in-out asymmetry ratio of q$_{t,out}$/q$_{t,total}$ increases with the power across the separatrix P$_{loss}$. The characteristics of the measured SOL parallel flow under various discharge conditions are consistent with the Pfirsch-Schl\"uter (PS) flow with the parallel Mach number M$_{\vert \vert}$ decreasing with the line averaged density but increasing with P$_{loss}$, in the same direction as the PS flow. The mechanisms of divertor asymmetry are investigated by the BOUT$++$ simulation.