Investigation of cumulation processes by converging strong shockwaves in various geometries

TYPEPhD seminar
Speaker:Daniel Shafer
Affiliation:Physics Department Technion
Location:Lidow 620
Abstract: The presented research is devoted to the study of converging strong shockwaves (SSW), produced by underwater electrical wire explosion (UEWE), and the phenomena that accompany them, namely, cumulative strong shock waves (SSW), water flows and high-velocity jets. This subject relates to the warm dense plasma which has fundamental (astrophysics, transport coefficients of the material at extreme conditions, equation of state), and applied interests (inertial confinement fusion, shock wave generation).This research deals with converging SSW with annular, “X-pinch” and conical geometries, created by ring-shaped wires, wires crossed at an acute angle and conical wire arrays, respectively.  It was shown that UEWE of ring-shaped wire creates toroidal SW, whose center-facing front is converging with a constant velocity.The UEWE of wires in the X-pinch configuration has generated two fast copper jets, which were ejected in the opposite directions from the hot spot towards the bisectors of the acute angles set by the wires.  Finally, the investigation of the explosions of conical wire arrays has shown that a state of continuous cumulation is achieved in this configuration, which results in ejection of fast jets into the air above the array. In these experiments, the shape and the velocity of the water jets and the shockwaves that accompany them in air, were found to depend on the apex angle of the conical wire array, on the energy deposition rate and on the thickness of the water above the array.