Diagnostics of a converging strong shock wave generated by underwater electrical explosion of spherical wire array

Abstract

Summary form only given. The results of experimental studies of a converging shock wave generated by underwater electrical explosion of a spherical wire array are reported. Two high-current generators, sub-microsecond (~ 350 ns rise time and ~550 kA current amplitude) and microsecond (~1.1 μs rise time and ~300 kA current amplitude) timescale were used for wire array explosion. In the latter case, addition energy was transferred to the water flow by the imploding wire array due to the global pressure of the discharge current. In experiments, power and spectrum of self-light emission from an optical fiber, deformation of a copper tube and the time depended resistance <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> of a carbon resistor placed in the equatorial plane of the wire array were measured to estimate the symmetry of the convergence. The results obtained were compared to the results of one dimensional hydrodynamic simulation, coupled with equation of states of water <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The comparison showed that the shock wave keeps its uniformity along the major part of the convergence towards the implosion origin. The latter allows one to consider generation of water in extreme conditions (~6·10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> Pa, ~17 eV, ~8 g/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> in the vicinity of the implosion origin.