Transport and sound waves in plasmas with light and heavy ions

We calculate the collisional damping of ion acoustic waves for a mixture of light and heavy ions. The results are strikingly different from those using the single-species average-ion model. The correct result includes a new Joule term as well as thermal diffusion and viscous damping terms. In a CH plasma, the thermal diffusion term is enhanced by a factor of 60 and the viscous damping by a factor of 5. The overall damping rate is dominated by the Joule term and is increased by at least 58-fold.