In simulation of a charged particle's guiding-center orbit in Tokamak equilibrium configurations, an efficient way to build physical functions such as magnetic field was obtained. Discrete Fourier transform is applied to replace cubic spline interpolation and B spline interpolation methods in calculation of gulding-center's trajectory. It has same accuracy as cubic spline interpolation and facilitates calculations in tearing mode as well. The method holds naturally property of symmetry. Derivatives of 3rd order or above can be obtained easily. Moreover, effect of incorrect data is reduced to the minimal limit compared with cubic spline interpolation.

Resonance absorption of p-polarized electromagnetic wave by mode conversion in magnetized inhomogeneous plasma is investigated numerically as external magnetic field is perpendicular to density gradient.Different from an unmagnetized inhomogeneous plasma,the mode conversion coefficient in a magnetized inhomogeneous plasma depends on a cooperation of the incident direction,the density gradient direction and the direction of external magnetic fied.