Integrated Robust Control of Individual Scalar Variables in Tokamaks

A. Pajares and E. Schuster

58th IEEE Conference on Decision and Control

Nice, France, December 11-13, 2019

Abstract

Tokamaks are devices with a toroidal shape in which a high-temperature ionized gas (plasma) is confined by means of helical magnetic fields. The final goal of these devices is to obtain energy from thermonuclear fusion reactions within this plasma. A multitude of coupled control problems arise in tokamak-plasma research that need to be solved simultaneously. For tokamaks to be able to operate safely while maximizing plasma performance, integrated control schemes that can handle different aspects of the plasma dynamics must be developed. Moreover, due to the inherent uncertainty that exists in the plasma modeling process, such controllers must be robust against unknown variations of the plasma behavior. In this work, a nonlinear, robust controller is designed for simultaneous regulation of magnetic and kinetic scalar variables, namely the central safety factor, q0, the edge safety factor, qedge, the total stored energy, W, and the global toroidal rotation, Ωφ. The controller is synthesized from physics-based, zero-dimensional (0D) models of the individual scalars’ dynamics. One-dimensional (1D) simulations using the COTSIM (Control- Oriented Transport Simulator) code are employed to test the proposed controller in a DIII-D scenario.