An Inverse Problem Originating from Magnetohydrodynamics II. The Case of the Grad-Shafranov Equation

The socalled Grad-Shafranov equation is a semilinear elliptic equation which is commonly used to model the plasma equlibrium in a Tokamak. We study an inverse problem associated with this equation. We show that knowledge of the normal derivative of the poloidal magnetic flux on the plasma boundary uniquely determines the functional form of the source terms within the class of analytic functions, provided the boundary has a (certain type of) corner. This result may in some ways be seen as an extension of a previously established result for the equation DELTAu = -f(u) less-than-or-equal-to