Underwater electrical wire explosion (UEWE) of the copper wire of 0.3 mm in diameter and 50 mm in length at high and low initial stored energies was compared. For this wire, the completely vaporization energy is 194 J. While the UEWE at high initial stored energy of 961 J show a good reproducibility, the shock waves generated by UEWE at low initial stored energy of 120 J have a poor reproducibility that is attributed to the partial vaporization of the exploding wire. As the initial stored energy was gradually increased from 110 to 1000 J, the deposition energy in the exploding wire was increased from 92 to 246 J. When the deposition energy is higher than the complete vaporization energy of the wire, the relative error in the shock wave is significantly reduced to 4%. The effect of the wire diameter on the UEWEs was investigated by keeping the initial stored energy at 120 J. It was observed that there exist two discharge modes, the mode of the cutting-off current with a partial vaporization for the wires of a diameter smaller than 0.5 mm and the mode of the continuous discharge with no vaporization for the wire of 0.5 mm in diameter. It was found that a partial vaporization of a vaporization rate as low as 6% is enough to generate the shock wave and the amplitude of the shock wave is determined by the vaporized mass of the wire. The more the vaporized mass, the higher is the shock wave.

The shock waves generated by an underwater electrical wire explosion were investigated. A microsecond time-scale pulsed current source was used to trigger the electrical explosion of copper wires with a length of 5 cm and a diameter of 200 μm. The energy-storage capacitor was charged to a relatively low energy so that the energy deposited onto the wire was not large enough to fully vaporize the whole wire. Two shock waves were recorded with a piezoelectric gauge that was located at a position of 100 mm from the exploding wire. The first and weak shock wave was confirmed to be the contribution from wire melting, while the second and stronger shock wave was the contribution from wire vaporization. The phenomenon whereby the first shock wave generated by melting being overtaken by the shock wave due to vaporization was observed.

Many research fields demand a pulsed power modulator capable of generating high-voltage arbitrary waveforms that are different from typical rectangular pulses. In this article, a new distributed high-voltage arbitrary waveform generator composed of multiple “standard” versatile pulsed power modules (VPPMs) is proposed. Each VPPM, based on the cascaded expanded full-bridge (EFB) cells, integrates the complete functional parts and has the same terminals. Therefore, multiple VPPMs can be connected directly and operate independently, in series or in parallel. In order to solve the problem of driving a large number of switches at different potentials, a new driving system based on magnetic isolated drive circuits is used. According to this design concept, three VPPMs with eight-stage EFB cells were developed and combined in different ways to construct the distributed pulse power supply with different configurations. The test results are also given: the single VPPM achieves the maximum output voltage of $\pm$ 7 kV and a total of 17-level voltage output; when three VPPMs operated in series, the maximum 49-level arbitrary waveforms with an amplitude of $\pm$ 20 kV were obtained; in the case of operating in parallel, the voltage drop of the output pulse decreases obviously.

Atmospheric pressure plasma jets (APPJs) can be driven by positive pulses, negative pulses, and sinusoidal ac excitations. The plasma jets under different excitations have different characteristics. In this article, a plasma jet system driven by three different power sources is established. The electrical and spectral characteristics of the jet as well as the vibration and rotation temperature of the plasma are studied. The results show that the peak discharge current of the pulsed plasma jet occurs along the rising and falling edges of the pulse voltage. The ac plasma jet will randomly appear with multiple discharge current pulses, but the peak current is much smaller than that of the pulse discharge current, and the input power of the sinusoidal ac plasma jet is significantly higher than that of the pulsed plasma jet. With the increase of discharge voltage, the length of the three plasma jets increases gradually, and the positive pulse plasma jets are the longest at each voltage. The luminescence intensity of three excitation particles (OH at 309.0 nm, N2 at 337.1 nm, and N2 at 357.6 nm) under three power sources was analyzed. The intensity of active particles in ac plasma jet is higher near the nozzle. With the increase of axial distance, the intensity of excited active particles in the positive-pulsed plasma jet increases. The rotating temperature of ac jet is 20–30k higher than that of pulse jet. The vibration temperature of pulsed plasma is higher than that of ac plasma jet. With the increase of jet axial distance, vibration temperature and rotation temperature change little.

In order to investigate the effect of the current rise rate on the underwater electrical wire explosion (UEWE), two pulsed sources were used. One pulsed power source used an energy-storage capacitor of 1 μF while the other used a 200 μF capacitor. These two capacitors were charged to the same energy. The ratio of the current rise rate was about 11 for the UEWEs using these two pulsed sources at the same stored energy. In addition to the rise rate of the current, the wire resistance played an important role in affecting the energy deposition when it was comparable or even lower than the circuit resistance. The experimental results indicated that different capacitors may also lead to different discharge modes, even under the same energy storage and using the same size copper wire. It was found that the deposition energy, deposition power, the deposition ratio, and the discharge mode may influence the shock wave.