Off-axis Neutral Beam Injection as a Tool for Expanding the Operating Space of DIII-D High $f_{NI}$ Discharges

The newly installed capability for 5~MW off-axis neutral beam injection is being utilized to broaden the pressure and current density profiles and raise the minimum $q$ value in DIII-D discharges with noninductive current fraction $f_{NI}$ near 1. Broader pressure is expected to allow stable access to increased $\beta_N$ and increase the bootstrap current density $J_{BS}$ off-axis. Reducing the on-axis current drive allows access to higher $q_{min}$, increasing the on-axis $J_{BS}$ and improving tearing mode stability. This is a path toward DIII-D (and a steady-state powerplant) $f_{NI}=1$ discharges at $q_{95} = 5$, which require $\beta_N \geq 4$. Initial experiments have demonstrated $q_{min}$ maintained above 2 with broader pressure profiles than previously observed. Analysis of the noninductive current profiles and high $\beta_N$ stability of discharges with off-axis beam injection will be presented