Addressing the Problem of Uniform Converging Spherical Shock Wave in Water

Time-resolved parameters of plasma compressed by a shock wave generated by the underwater electrical explosion of a spherical wire array are presented. The plasma was preliminarily formed inside a capillary placed at the equatorial plane along the axis of the array. Temporal evolution analysis of Hα and C II spectral lines showed that the plasma density increases from its initial value of ∼3 × 1017 cm−3 up to ∼5.5 × 1017 cm−3 within 300 ± 25 ns. These results were found to be in agreement with those of the model that considers the adiabatic compression of the plasma by the converging capillary walls caused by interaction with the incident shock wave with a pressure of ∼3 × 109 Pa at a radius of 1.5 mm. The latter results coincide well with those of the 1D hydrodynamic modeling, which assumes uniformity of the converging shock wave.