Effects of 3D Magnetic Perturbations on DIII-D Reconstructed Equilibria

Non-axisymmetric perturbation magnetic fields are routinely applied in \hbox{DIII-D} experiments to study and control MHD modes. The effects of the perturbation fields on the background 2D equilibrium are studied using a set of recent \hbox{DIII-D} single- and double-null \hbox{H-mode} discharges with varying amount of \hbox{I-coil} perturbations. The reconstructed vertical positions of the plasma separatrix boundary at the \hbox{DIII-D} Thomson diagnostic viewing chord are compared against those estimated from the measured edge electron temperature profiles. For lower single-null and double-null plasmas, the reconstructed vertical boundary locations generally agree with those estimated from the edge temperature profiles within $\sim$1 cm. For upper single-null plasmas, the differences in the Thomson boundary locations tend to be greater. The effects of the perturbation fields on the 2D reconstructed equilibria are also being analyzed using a set of 3D codes TRIP3D without and \hbox{MARS-F} and VMOM3D with plasma response. Details will be presented.