Mathematical modeling of the magnetic response of thin superconducting disc according to critical state model with a critical current density with inverse-square dependance of field magnitude

In this work carry out mathematical modeling of magnetization harmonics of hard superconductors two type for thin disk. According to critical state model with $J_c \sim \gamma / H^2$ in approximation of magnetic field screening in the disk center has calculated hysteretic magnetization curves and magnetic field and temperature dependencies magnetization harmonics. Quality influence of magnitude of ac magnetic field amplitude was found on harmonic magnetization. The results this work was compared with experimental results for polycrystals of high-temperature superconductors. The parameter of model $\gamma$ was estimated