Initial Results from the New Internal Magnetic Field Coils for Resistive Wall Mode Stabilization in the DIII-D Tokamak

OAK-B135 A set of 12 internal magnetic field coils (I-coils) has recently been installed and is being used in 2003 experiments. The purpose of this new coil set is to provide stabilization of resistive wall modes (RWM) for advanced tokamak plasmas with toroidal {beta} above the no wall stability limit. Calculations with the 3D electromagnetic code VALEN predict that the performance of this system should be superior to the previously installed external compensation coils (C-coils) by providing feedback stabilization up to the ideal wall beta limit without the need for strong plasmas rotation, which was required in previous DIII-D experiments. Initial results have shown that with feedback this I-coil set can stabilize the RWM well above the no wall limit and simultaneously reduce the resonant field amplification (RFA) process allowing high toroidal rotation. With the I-coil fewer Amp-turns are required than with the existing external C-coil set. In this paper they will discuss these results, and other uses of the I-coils.