To explore the double null (DN) divertor configuration and the corresponding plasma current (I_p)operation space for supporting the Mega-ampere plasma current operation in the HL-3 tokamak, the relationship between the safety factor q₉₅ and the equilibrium configuration is determined. Combined with the HL-3 first wall structure and the contours of the upper divertor target plate with three different conceptual designs, the free boundary equilibrium code FEEQS is used to design the DN divertor configuration with variant parameters under Ohmic heating. Considering the engineering requirements, the optimal DN configuration parameters such as plasma current I_p =2.5 MA, the toroidal field B_T=2.5 T, elongation к=1.78, triangularity δ=0.65 (for B_T=3 T, I_pmax=3 MA) are clarified when q₉₅ is not less than 3. For the need of the closed divertor research, the feasible optimization design of the upper single null configuration is further carried out for I_p =2 MA, B_T =2.2 T, к =1.64,δ=0.56. These designs provide references for the upper divertor physical research and the operation of the Mega-ampere plasma current discharge on HL-3 tokamak.

Configuration parameters space, Mega-ampere plasma current configuration, Free boundary equilibrium

为了探索支撑 HL-3 装置兆安培等离子体电流运行的双零偏滤器位形及对应的等离子体电流 I_p运行区间，建立了安全因子 q₉₅与平衡位形的关系。结合装置第一壁结构与 3 种不同概念设计的上偏滤器靶板轮廓，利用自由边界平衡代码FEEQS 设计欧姆加热下不同参数的双零偏滤器位形。综合考虑工程需求，明确了 q₉₅不低于 3 时可选双零位形参数。如：等离子体电流 I_p为 2.5 MA、环向场 B_T为 2.5 T、拉长比 к 为 1.78、三角形变 δ 为 0.65(B_T=3 T 时，I_pmax=3 MA)；其次对于面向封闭偏滤器的研究需求，进一步开展了在 B_T=2.2 T 时上单零偏滤器位形优化设计，可运行 I_p=2 MA、к=1.64、δ=0.56 的上单零位形。这些设计为 HL-3 装置的上偏滤器物理研究、兆安培电流等离子体放电运行提供了参考。

位形参数空间, 兆安培等离子体电流位形, 自由边界平衡