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)
— 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(More)
— The paper proposes a model-based control approach for the coupled evolution of the poloidal magnetic flux profile and the normalized pressure ratio βN. The model is determined by a system identification method which is shown to sufficiently reproduce the plasma response to variations in particular actuators. Data for model identification is collected(More)
— System identification techniques have been successfully used to obtain linear dynamic plasma response models around a particular equilibrium in different tokamaks. This paper identifies a two-timescale dynamic model of the rota-tional transform ι profile and β N in response to the electric field due to induction as well as to heating and current drive(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(More)