The influence of isotope on ablation rates concerning the material mass Mi , sublimation energy Um and molecular density nm , for five combinations of solid isotopic hydrogenic pellets H2, HD, D2, DT, T2 have been studied. The results show that inject ion with the DT or T2 fuelling pellet leads to deeper pellet material deposition. Under the same plasma condition and initial pellet parameters, the penetration depth for tritium pellet increases by ~ 40% in comparison with that of hydrogen pellet. The ITER core fueling difficulty will be moderately alleviated by taking the isotope effects into account . The significant improvement of core fueling with pellet inject ion from high field side (HFS) in the midplane has been presented. By considering the effect of non-uniform tokamak magnetic field, the vertical drift current inside the ionized ablatent produces the polarization that causes the charged ablatant drifts in the direction of the outward major radius. Numerical simulation calculations show that the ablated substance of pellet can be deposited to the core region even with the initial velocity of pellet as low as a few hundred meters per second.
