Negative-Triangularity Configuration on EAST: Analysis of engineering limitations on superconducting, D-shaped, target-diverted plasmas

In recent years, tokamak research has repeatedly shown that the edge magneto-hydrodynamic stability is critical for handling the power to the walls and the divertor plates which is now and will mostly likely continue to be a limiting factor in the International Thermonuclear Experimental Reactor (ITER) and the DEMOnstration Power Station (DEMO). Recent experiments at Tokamak \`{a} Configuration Variable (TCV) [Medvedev et al.] and DIII-D [Austin et al.] have shown that a Negative-Triangularity Configuration (NTC) has a larger power handling area on the Low-Field-Side (LFS) divertor target plate [Medvedev et al.] and improved edge stability. However, there have been relatively few NTC experiments performed so far and none of them have been performed on a superconducting tokamak with shaping capabilities similar to ITER. To expand upon the previous experiments on TCV and DIII-D this paper addresses an initial test of the NTC capability of the Experimental Advanced Superconducting Tokamak (EAST) which has achieved a 7 s ohmic discharge Upper Singular Null (USN) target-diverted plasma with a lower traingularity of $\delta_L \le -0.09$.