John R. Ferron

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Setting up a suitable current spatial profile in tokamak plasmas has been demonstrated to be a key condition for one possible advanced scenario with improved confinement and possible steady-state operation. Experiments at the DIII-D tokamak focus on creating the desired current profile during the plasma current ramp-up and early flattop phases with the aim(More)
In tokamak fusion plasmas, controlling the spatial distribution profile of the toroidal current is key to achieving advanced scenarios characterized by confinement improvement and possible steady-state operation. The dynamics of the current profile are nonlinear and coupled with other plasma parameters, motivating the use of model-based control strategies.(More)
Setting up a suitable toroidal current profile in a fusion tokamak reactor is vital to the eventual realization of a commercial nuclear fusion power plant. Creating the desired current profile during the ramp-up and early flat-top phases of the plasma discharge and then actively maintaining this target profile for the remainder of the discharge is the goal(More)
The tokamak is a device that utilizes magnetic fields to confine a reactant gas to generate energy from nuclear fusion reactions. The next step towards the realization of a tokamak power plant is the ITER project, and extensive research has been conducted to find high performance operating scenarios characterized by a high fusion gain and plasma stability.(More)
The software structure of the plasma control system in use on the DIII–D tokamak experiment is described. This system implements control functions through software executing in real time on one or more digital computers. The software is organized into a hierarchy that allows new control functions needed to support the DIII–D experimental program to be added(More)
The potential operation of a tokamak fusion reactor in a highly-efficient, steady-state mode is directly related to the achievement of certain types of radial profiles for the current flowing toroidally in the reactor. The time evolution of the toroidal current profile is related to the poloidal magnetic flux profile evolution, which is modeled in(More)
Recent new and improved plasma control regimes have evolved from enhancements to the systems responsible for managing the plasma configuration on the DIII–D tokamak [1]. The collection of hardware and software components designed for this purpose is known at DIII–D as the Plasma Control System or PCS [2]. Several new user requirements have contributed to(More)
DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information,(More)