Study of the Relationship Between Maximum Specific Energy and Wire Diameter During Electrical Explosion of Tungsten Wires

Driven by a pulsed current of 1-3 kA in amplitude and 15-30 ns in risetime, electrical explosions of tungsten wires of different diameters (25/18/15/12.5/10 μm) were carried out. Shadowgraphs as well as interferograms of exploding tungsten wires were obtained with a YAG Laser. The experimental results showed that with the decrease in wire diameter, the maximum specific energy E
_sm
(the maximum deposition energy per atom), as well as the wire expansion speed has an increase-decrease tendency under both negative and positive current pulses. In order to understand this phenomenon, the specific power P
_v
at the start moment of vaporization was simulated, and the changing tendency of P
_v
versus diameter was found to be similar to that of E
_sm
versus diameter. Based on the experiments and simulations, we propose that the specific power P
_v
at the evaporating point must also be regarded as an important factor leading to the change in the maximum specific energy E
_sm
.