Z-pinch implosion of massive copper liners for study of phase transitions in carbon

Summary form only given, as follows. The experimental set-up on z-pinch implosion is described. In the set-up a cylindrical copper tube (liner) having wall with 1/spl divide/3 mm thickness is accelerated by electrodynamic forces arising when pulsed electrical current of 2/spl divide/4 MA magnitude is passed through the liner in the longitudinal direction. Inside the liner the steel tube with smaller diameter is placed. The steel tube is filled by graphite or contained graphite substance. In the experiments the inner surface of liner achieved a velocity of about 1 km/s. The graphite inside steel tube is exposed to shock loading when the liner impacts this tube. As a result the pressure inside steel tube achieves about 30 GPa; the temperature increases also. Under this conditions the graphite may undergo phase transitions, including the graphite-diamond phase transition. In our experiments we have received up to 4% of yellow crystalline carbon. The results of X-ray diffraction analysis of carbon exposed to shock loading, as well as the electron microscope photographs of crystallites are presented. The limitations on the electrical current magnitude and the liner velocity achieved in the experiments are considered.