Scaling Laws of Heat Flux Width in the HL-2A Closed Divertor Tokamak

The scaling law of divertor heat flux width is one of the key topics of magnetic confinement fusion,which is almost inversely proportional to the poloidal magnetic field on some opened divertor tokamaks.This work focuses on the scaling laws of the closed divertor heat flux width in the HL-2 A tokamak under different discharge conditions,such as the Ohmic,L-and H-modes.The results indicate that there are basic similarities of the scaling laws of the heat flux width between the opened and closed divertors.However,a larger spreading width in the private flux region is found,which is relevant to a small expansion factor of the magnetic flux in the closed divertor.