Shock compressibility of condensed materials in strong shock waves generated by underground nuclear explosions

An experimental investigation was made of the compressibility of condensed materials under the conditions of underground nuclear explosions. The majority of the measurements were absolute: they were carried out in the range 5—10 TPa for heavy materials and at 2 TPa for light materials. Iron, lead, copper, cadmium, molybdenum, aluminium, as well as quartz, water, and polymethyl methacrylate were investigated. The compressibility measurements were made not only on continuous samples, but also on porous samples of iron, copper, tungsten, and quartz. The results agree with the Thomas—Fermi calculation model with quantum and exchange corrections when nuclear interactions are taken into account. The slope dD/dU of the adiabats was 1.2 at ultrahigh pressures (above 1 and 0.3 TPa for heavy and light materials, respectively). In the range of pressures attainable in laboratory experiments the results were scaling-independent.