Eur. Phys. J. D 28, 381-392 (2004)
https://doi.org/10.1140/epjd/e2003-00322-3

Jump conditions in hypersonic shocks

Quantitative effects of ionic excitation and radiation

¹ LUTH, UMR 8102 du CNRS, Observatoire de Paris, 5 place J. Janssen , 92195 Meudon, France
² Department of Astronomy, University of Maryland, College Park, MD 20742, USA
³ NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771, USA

Corresponding author: ^a Claire.Michaut@obspm.fr

Received: 7 April 2003
Revised: 3 October 2003
Published online: 6 January 2004

Abstract

We study the quantitative effects of excitation, ionization, radiation energy and pressure, on the jump conditions in hypersonic shocks in a real gas. The ionization structure and excitation energies are calculated from the local temperature and density, using the Screened Hydrogenic Model. We assume an optically thick medium and no radiation flux through the shock front. We investigate the jump conditions in different gases and propose a phenomenological description of compression for different shock velocities. We find that the excitation energy term is the dominant term in ionized gases at low velocities. Consequently, higher shock velocities than the values predicted by standard calculations in a perfect gas must be reached in order to observe the effects of radiation in the compression ratio. Our results provide constraints for the design of future radiative shock experiments on the next generation of powerful nanosecond lasers or on Z-pinches.