Start-up phase plasma discharge design of a tokamak via control parameterization method

• Published in: Chinese physics B Vol. 24; no. 3; pp. 248 - 254
• Main Author: 郭珊 许珂 许超 任志刚 肖炳甲
• Format: Journal Article
• Language: English
• Published: 01.03.2015
• Subjects: Electric potential; Mathematical models; Optimization; Parametrization; Plasma (physics); Plasma currents; Tokamak devices; Variational methods; Voltage; 参数化方法; 常微分方程; 托卡马克; 控制参数; 数值模拟; 电设计; 等离子体电流; 非线性微分方程
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/24/3/035202

The tokamak start-up is a very important phase during the process to obtain a suitable equalizing plasma, and its governing model can be described as a set of nonlinear ordinary differential equations（ODEs）. In this paper, we first estimate the parameters in the original model and set up an accurate model to express how the variables change during the start-up phase, especially how the plasma current changes with respect to time and the loop voltage. Then, we apply the control parameterization method to obtain an approximate optimal parameters selection problem for the loop voltage design to achieve a desired plasma current target. Computational optimal control techniques such as the variational method and the costate method are employed to solve the problem, respectively. Finally, numerical simulations are performed and the results obtained via different methods are compared. Our numerical parameterization method and optimization procedure turn out to be effective.