Dialogue Concerning the Two Shock Codes

TL;DR

This paper compares two established shock codes, MAPPINGS and CR, analyzing their treatment of shock physics and radiative transfer to understand differences in their predictions of shock properties and emissions.

Contribution

It provides a detailed comparison of the shock physics and radiative transfer treatments in two widely used shock codes, highlighting their similarities and differences.

Findings

Both codes use Rankine-Hugoniot equations for shock flow.

Differences in radiative transfer treatment affect ionization and emission predictions.

The study emphasizes the importance of photoionization in shock modeling.

Abstract

In this paper, we summarize the shock physics and the treatment of radiative transfer in two well-established shock codes -- the MAPPINGS code (Dopita1976,Binette1985,Sutherland1993) and the Cox/Raymond code (hereafter CR code) (Cox1972,Raymond1976,Raymond1979). We compare the ionization states, temperatures, electron densities, and the energy transportation of the shock models with shock velocities of 50, 110, 150 and 300 km/s. In summary, both codes adopt the Rankine-Hugoniot flow equation to describe the shock flows, giving the same shock physical properties at the immediate area behind shock fronts. The different treatments of radiative transfer in these two codes leads to somewhat different computation of the ionization and thermal structures of shocks, as well as the emission-line fluxes. This work highlights the importance of the delicate treatment of photoionization in shock models, providing insight of the future development of shock codes, such as the 3D shock codes.