Method of Studying the State of Condensed Substances Near the Cold-Compression Curve at Extreme Pressures

Using an experiment with a lead shell as an example, a method for studying the quasi-isentropic compressibility of condensed substances was tested based on the use of multiframe radiography and explosive spherical loading devices with gas symmetrization. At the moment of maximum compression, the average density of the lead shell of 1pt 52. 3 g/cm3 is reached and the compression ratio is 1pt 4. 6 in this case. Total pressure in lead at the moment of maximum compression was 1pt 3. 2 TPa, while the cold component was equal to ≈94% and thermal was ≈6%. The pressure values were obtained from a one-dimensional numerical calculation, which describes with high accuracy the compression dynamics of the lead shell, using ROSA-MI EOS for lead.