Effect of the prepulse current with an adjustable time-delay on the implosion dynamics of two-wire Z-pinch

Abstract

Experiments are performed on the 'Qin-1' double pulse current generator at Xi'an Jiaotong University to study the effect of the prepulse current on the implosion dynamics of two-wire Z-pinches. An independent prepulse current with an adjustable time-delay (T delay ) is introduced to preheat the wires before the start of the main pulse current. An estimation of the deposited energy and the areal density reconstructed from the interferogram suggest that the wires are partly vaporized with a gasification fraction of ∼67%. The prepulse preconditioning has a redistribution effect on the load mass, which determines the subsequent implosion process. The planar implosion of the two-wire load with a preset T delay ⩽ 450 ns can be divided into the two-layer phase and the merged implosion phase. The snowplow-like implosion is the main characteristic of the shot with a 1050 ns T delay . The ablation streams gradually disappear with the increasing T delay . The proportion of the mass that participates in implosion is increased as the preset T delay increases from 120 ns to 1050 ns.

Study of ablation phase in double-wire Z-pinch based on optical Thomson scattering

“…The experiment was performed using the Qin-1 pulse power generator (400 ns, 350 kA) with a voltage of ±35 kV [16,17]. The load consisted of two aluminum wires with a diameter of 20 µm, a width of 12 mm, and a height of 20 mm.…”

Experimental study of the magnetic field and current distribution in double-wire Z-pinch

“…Experiments were conducted on the 'Qin-1 ′ facility at Xi'an Jiaotong University utilizing a maximum current of 450 kA/400 ns [25,26]. The load was composed of two aluminum wires placed 12 mm apart, with a diameter of 20 µm and a height of 20 mm.…”

Study of the electrothermal and MHD instabilities in exploding cylindrical foil liner

“…The diagnostic setup inside the vacuum chamber is shown in figure 3(a). Along the radial direction, a 30 ps pulse width 532 nm Nd-YAG laser is used for the multi-frame shadow imaging system to observe the ablation dynamics and perturbations at the outside edge of the liner [24]. The spatial resolution of our multi-frame laser shadow imaging system is considered to be 10-20 μm.…”