Developing the advanced tokamak-recent progress at DIII-D

The DIII-D tokamak has made a remarkable series of contributions to the fusion science program. These contributions are due to the continual evolution of the experimental systems led by research results and technological developments. The recent completion of core and edge diagnostics allows comprehensive time-dependent profile data, including plasma current and rotation profiles to be available on each discharge. This data combined with rapid a MHD calculation of the flux surfaces is used to carry out extensive analysis between discharges (10-15 min cycle) and permits a shot-by-shot strategy to optimize research productivity. The control of the plasma internal profiles has emerged as key in developing advanced tokamak discharges. RF power has become a key tool in achieving this control. The DIII-D ECH system is presently being expanded to a capability of six MW level gyrotrons. The radiative divertor configuration has evolved as an effective tool for edge plasma management. The recent commissioning of the upper outer divertor cryopump and baffle along with the existing installation in the lower divertor has allowed understanding of the role of upper and lower divertors, double-null divertors, and the location of the X-point. This fall, installation of an upper inner cryopump and baffle will allow further investigation of the role of pumping of the private flux region of the high triangularity divertor.