Description
We develop a multi-ion closure framework for tokamak plasmas by solving the drift-kinetic equation using the moment-Fourier method. The model extends our previous single-ion formulation to plasmas containing multiple ion species and consistently incorporates inter-species collisional effects in the moment system. As a representative case, we consider a deuterium–carbon plasma, assuming a common zeroth-order ion temperature on each flux surface while allowing the electron temperature to differ. The first-order fluid moments, namely density, temperature, and parallel flow velocity, are computed for electrons, deuterium ions, and carbon ions. The framework enables a direct comparison of the first-order parallel flow velocities of deuterium and carbon ions, thereby providing a quantitative basis for interpreting charge-exchange spectroscopy measurements and for systematic multi-ion neoclassical transport studies.