As. Demidov et al., ON INVERSE AND DIRECT FREE-BOUNDARY PROBLEMS IN THE THEORY OF PLASMA EQUILIBRIUM IN A TOKAMAK, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 323(4), 1996, pp. 353-358
Theorems of existence of simply connected ''plasma'' domain for the cy
lindrical case of the Grad-Shafranov equation Delta u = F(u) are given
. For the inverse problem upper and lower estimates of normal derivati
ve of u on the boundary of the ''plasma'' domain are obtained.