ANALYSIS AND APPROXIMATION OF OPTIMAL-CONTROL PROBLEMS FOR A SIMPLIFIED GINZBURG-LANDAU MODEL OF SUPERCONDUCTIVITY

This paper is concerned with optimal control problems for a Ginzburg-L andau model of superconductivity that is valid for high values of the Ginzburg-Landau parameter and high external fields, The control is of Neumann type, We first show that optimal solutions exist. We then show that Lagrange multipliers may be used to enforce the constraints and derive an optimality system from which optimal states and controls may be deduced. Then we define finite element approximations of solutions for the optimality system and derive error estimates for the approxim ations. Finally, we report on some numerical results.