Nanosecond electrical explosion of bare and dielectric coated tungsten wire in vacuum

Abstract

Experiments of the electrical explosion of tungsten wire with and without insulating coatings demonstrate that the insulating coatings exert a significant influence on the exploding characteristics. The shadowgraphy and interferometry diagnostics are applied to present the morphology of the exploding products. In the experiments, energy of ∼3.2 eV/atom is deposited into the bare tungsten wire at the instant of voltage breakdown, giving a velocity of 0.38 km/s for the high density core. The value and structure of the energy deposition for the tungsten wire explosions are substantially improved by employing the thin dielectric coatings. Energy of ∼15.2 eV/atom is deposited into the coated tungsten wire transforming the wire into gaseous state and the expanding velocity of the high density core is 5.64 km/s. The interference phase shift and atomic density are reconstructed from the interferogram for the exploding coated tungsten wire.