Nonlinear Control Schemes for the Injection of Electron Cyclotron Waves in Magnetic Fusion Plasma

The fusion process can be exploited for electricity production by proposed reactors in power plants that are still in the experimental stage. These devices require extremely high temperatures to achieve fusion, causing the gaseous fuel to ionize and resulting in a fluid state of matter known as plasma. Plasma is characterized by numerous instabilities, which require timely and effective mitigation to ensure both the smooth operation and the safety of the reactor. Microwave sources are widely used for suppressing instabilities and heating the plasma, utilizing waves of appropriate frequency, power, and direction. Control theory provides tools for precise and rapid targeting to optimize microwave emission applications. The purpose of this paper is to model and simulate a nonlinear control system for a targeting mechanism that will operate under strict specifications and contribute to the smooth operation of the reactor. Initially, the feedback linearization method is applied to the nonlinear dynamics of the ideal model, followed by the inclusion of the sliding mode control method to compensate for errors and suppress unpredictable dynamics. In addition, using plasma wave physics, the optimal emission angle will be studied as a reference input to the control system as an example of its application to target a specific type of instability (neoclassical tearing modes), based on parameters from the ASDEX device.