Splitting shock heating between ions and electrons in an ionized gas

When a shock passes through an ionized plasma, a question exists about how much of the shock energy should go to the ions and how much should go to the electrons. Until recently, we have used the simplest possible model (based on Zel'dovich and Raizer [1], dumping all of the shock energy into the ions and ignoring the electronic fluid completely. However, we have become aware of work from the early 2000's by Velikovich et al. [2] that has convinced us that a more sophisticated approach can be worthwhile in problems that involve ionization of elements with atomic number (Z) as low as five or six. We describe an approach for splitting the shock energy according to the values of ion and electron viscosity. We examine several calculations to explore the difference between our previous approach and our new one. Finally, we conclude with a brief discussion of when ion/electron shock heat splitting will matter and when it will not, along with some ideas for future research. (C) 2020 The Author. Published by Elsevier Ltd.