Mark D. Boyer

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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)
One of the most promising devices for realizing power production through nuclear fusion is the tokamak. To maximize performance, it is preferable that tokamak reactors achieve advanced operating scenarios characterized by good plasma confinement, improved magnetohydrodynamic stability, and a largely noninductively driven plasma current. Such scenarios could(More)
The control of plasma density profiles is one of the most fundamental problems in fusion reactors. During reactor operation, the spatial profiles of deuterium-tritium fuel, alpha-particles generated by fusion reactions, and energy must be precisely regulated. Here we apply a backstepping boundary control technique to stabilize an unstable equilibrium in a(More)
The tokamak is a high order, distributed parameter, nonlinear system with a large number of instabilities. Therefore, accurate theoretical plasma models are difficult to develop. However, linear plasma response models around a particular equilibrium can be developed by using data-driven modeling techniques. This paper introduces a linear model of the(More)
The control of plasma density and temperature are among the most fundamental problems in fusion reactors and will be critical to the success of burning plasma experiments like ITER. While stable burn conditions exist, it is possible that economic and technological constraints will require future commercial reactors to operate with low temperature, high(More)
For nuclear fusion to become an economical means of producing energy, tokamak reactors will have to operate at high fusion gain (the ratio of power produced to power required to sustain a discharge) for extended durations, ideally reaching steady state. In present-day experiments, much work is being done to identify operating scenarios that could lead to(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-time-scale dynamic model of the rotational transform ι profile and βN in response to the electric field due to induction as well as to heating and current drive (H&CD)(More)