Reversed Magnetic Shear Scenario Development in NSTX-U using TRANSP

Understanding and control of electron thermal transport is a critical point of research in magnetic fusion experiments. Previous experiments have shown that operation with reversed magnetic shear (RMS) can suppress electron thermal transport through the generation of internal transport barriers (ITB), with the location of the ITB correlated with the location of minimum magnetic shear. The recent upgrades to NSTX, increased magnetic field up to 1 T, increased plasma current up to 2 MA, 2^nd neutral beam, present an increased operating space in which to explore electron thermal transport in RMS plasmas. Utilizing TRANSP, we have developed operating scenarios by which to generate RMS plasmas in NSTX-U. The results suggest that RMS in NSTX-U can be generated through a fast current ramp and early beam injection into a large plasma volume. This is very similar to the procedure that was followed in both TFTR and NSTX to generate RMS. Sustainment of RMS, disregarding non-q_min = 1 MHD events, required maintaining a large plasma volume, decreasing the peak plasma current and increasing the toroidal field. Using this procedure, RMS was sustained for 1.5 s, with q_min > 1 for the entire simulation.