Shock experiments on minerals: Basic physics and techniques
About half a century ago the first experimental shock techniques and the basic laws governing the propagation of shock waves have been developed. During these early post-war years Russian and American pioneers were already able to experimentally compress solids to half of their specific volumes (see Trunin, 1998, or Zel’dovich & Raizer, 2002, for a review), i.e. pressures prevailing in the Earth’ s core were reproducible in laboratory shock experiments long before static compression techniques such as the diamond anvil cell approached this limit. The strength of shock experiments particularly lies in the fact that a combination of high pressures and high temperatures can be achieved, while the attainment of high temperatures is still problematic in diamond anvil cell experiments.
In Earth and planetary sciences there are numerous basic interests in employing shock techniques. On one hand, shock experiments are devoted to the measurement of the shock wave equation of state of minerals and rocks at extreme conditions (Wackerle, 1962; Grady, 1977; Marsh, 1980; Ahrens, 1987, 1993; Boslough & Ahrens, 1984; Ahrens & Johnson, 1995a, 1995b). Virtually, the entire range of pressures and temperatures prevailing in the Earth’ s and planetary interiors can be reproduced in the laboratory. In this context, important applications of shock wave data are the correlation of the pressure–density function with the inner structure of planets and the assessment of the melting temperatures at which planetary magma oceans can be produced.