Experimental Investigation of ITER Startup and Rampdown Scenarios in the DIII-D Tokamak

ITER scenario studies have focused on the current flattop phase, but reaching current flattop and successful discharge termination (i.e. a ``soft landing") must also be considered. Experiments in DIII-D have simulated ITER discharges including low inductive electric field ($E_\phi \leq0.3\,$V/m), startup limiting on the low field side (LFS), and $\ell_i$ control mostly for vertical stability control. ITER-like LFS startup has been achieved in two scenarios: constant $q_{95}$ (small bore) and a larger volume diverting earlier in time to reduce heat flux to the outer wall (large bore). With a large bore startup, both hybrid and ITER baseline H-mode discharges have been obtained during the flattop phase. We will present the effects of variations in density, auxiliary power, and current ramp rate on $\ell_i$. Low voltage startup, $V_{loop} \geq2.2\,$V (0.21~V/m) with EC assist will be discussed and initial results simulating the ITER rampdown phase will also be presented.