Dynamic Experiments: an Overview
Dynamic high pressures are applied rapidly to materials to increase density and temperature, to alter. crystal structure and microstructure, and to change physical and chemical properties [1]. These effects are achieved at high pressures and many are retained on release from high pressures. Today it is possible to achieve pressures of order 50 to 500 GPa (5 Mbar), compressions up to fifteen fold greater than initial solid density in the case of hydrogen, and temperatures ranging from 1 K up to several ev (11,600 K) in condensed matter. At these extreme conditions the bonding , structure, physical properties and chemistry of condensed matter are changed substantially from what they are at ambient. This in turn opens up a whole new range of opportunities for novel condensed matter physics, chemistry, and planetary research at extreme conditions. If high pressure phases could be quenched to ambient, then new opportunities would become available in condensed matter and material sciences, as well as for technological applications. This article is concerned with high pressures achieved dynamically by shock compression [2]. In fact, the terms dynamic and shock are used interchangably to describe pressure pulses above 1 GPa (10 kbar) or so. Because dynamic compression is so fast, the process is adiabatic and temperature increases. Shock compression is achieved by high velocity impact obtained with light-gas guns (two-stage, single-stage, and powder guns), pulsed lasers, high pulsed electrical currents, and explosives. In this article we are concerned with strong shock compressions; that is, those which occur in a time of the order of a ps and for which the pressure exceeds 1 GPa. Typical durations of the pressure pulse are a few 100 ns, a few ns, a few 10 ns, and a few 1000 ns for guns, lasers, pulsed currents, and explosives, respectively.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15003022
- Report Number(s):
- UCRL-JC-144593; TRN: US200420%%264
- Resource Relation:
- Conference: International School of Physics''Enrico Fermi'' Course on''High Pressure Phenomena'', Varenna (IT), 07/03/2001--07/13/2001; Other Information: PBD: 6 Jul 2001
- Country of Publication:
- United States
- Language:
- English
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