In plasmas, where there are various collective phenomena, the type of electromagnetic waves that can propagate into the plasma is limited by plasma parameters and other factors. Effective radio-frequency (RF) heatings have been explored in fusion reactors. Still, the kinds of these ions and their ratios make the accessibility for the waves that can propagate and be absorbed on the plasma core. In this assignment, students will learn the basics of wave propagation in plasmas, investigate the conditions of wave propagation and absorption when using multiple types of ions, and deepen their understanding of RF wave propagation in plasmas.