Dependence of the critical temperature of cylindrical superconductors on the boundary conditions

The paper presents the results of a study of the properties of long cylindrical superconductors with a diameter of the order of coherence length $\xi$, performed in the framework of the Ginzburg–Landau theory (GL). Boundary conditions of general form are used for solution of the GL equa-tion for superconducting order parameter. Using such boundary conditions allows us to take into account the influence of the cylinder boundary on its superconducting properties. This ap-proach is important for small-diameter cylinders, whose properties significantly depend on the properties of their boundaries.