Control of Plasma Stored Energy for Burn Control Using DIII-D In-Vessel Coils

A new approach has been experimentally demonstrated to control the stored energy by applying a non-axisymmetric magnetic field using the DIII-D in-vessel coils to modify the energy confinement time. In relatively low collisionality DIII-D discharges, the application of non-axisymmetric magnetic fields results in a decrease in confinement time and density pumpout. Control of the stored energy was demonstrated by the application of non-axisymmetric fields while using gas puffing to compensate the density pumpout in the pedestal. Since the fusion power in a power plant operating at high $Q_{DT}$ can be related to the plasma stored energy and hence, is a strong function of the energy confinement time, the application of non-axisymmetric fields may be an effective technique to adjust the fusion power in a power plant.