Density limits with different fuelling methods have been compared in HL-2A,i.e.directgas puffing and supersonic molecular beam injection(SMBI)from outer midplane,and divertorgas fuelling.The maximum densities for low current discharges are 3.4×l0^(19)m^(-3),4.3×l0^(-9)m^(-3)and 4.7×l0^(19)m^(-3)for the 3 kinds of fuelling methods.The corresponding density ratios to Greenwalddensity limit are 0.9,1.1,1.2,respectively.The behavior of density limit disruption isanalyzed as well.
