Inhomogeneity of currents in a wire array during its exploding phase

The current in a wire array during its exploding phase has been studied. Th e wire array consisting of many thin wires is used as a plasma source in a z-pinch X-ray radiation system. The current distribution in the exploding w ire array plays an important role in producing an initial symmetrical plasm a. In the present experiment, four tungsten wires of 0.1 min in diameter we re exploded in a vacuum. The experiment was carried out with an inductive v oltage adder pulsed power generator providing a current of 160 kA at quarte r period of 1.8 mus. The currents through and the voltage across the wires were measured simultaneously. It was found that the currents in the wires w ere inhomogeneous, especially after the wires became plasma. Once the curre nts became inhomogeneous, the inhomogeneity remained throughout the dischar ge. It was also studied how the dimensions of the wires affected the homoge neity of the currents. Wires of different lengths or different cross sectio nal areas resulted in strong inhomogeneities of the currents. The wires wit h shorter length or smaller cross-sectional area became plasmas earlier tha n other wires. Thus, the resistances of the wires were not equal. These dif ferences in the resistance caused the inhomogeneity of the currents.