A compact pulsed power driver with precisely shaped current waveforms for magnetically driven loading experiments

Abstract

Magnetically driven loading techniques based on high current pulsed power drivers are very important tools for researching material dynamic behaviors and high-pressure physics. Based on the technologies of a Marx generator energy storage and low impedance coaxial cable energy transmission, a compact high current pulsed power driver CQ-7 was developed and established at the Institute of Fluid Physics, China Academy of Engineering Physics, which can generate precisely shaped current waveforms for magnetically driven loading experiments. CQ-7 is composed of 256 two-stage Marx generators in parallel with low impedance, high voltage coaxial cables for current output. The 256 Marx generators are divided into 16 groups, and each separate group can be individually triggered to discharge and shape currents in sequence by a low jitter, high voltage pulse trigger with 16 output signals. The electrical parameters of CQ-7 are a capacitance of 20.48 µF, an inductance of 4.12 nH, and a resistance of 3.35 mΩ in a short circuit. When working at the charging voltage of ±40–±60 kV, CQ-7 can deliver a peak current from 5 to 7 MA to the short-circuit loads with a rising time of 400–700 ns at different discharging time sequences. Two different experiments were conducted to test the performance of CQ-7: magnetically driven high velocity flyer plates and solid liner implosion. The results show that CQ-7 can accelerate the aluminum flyer plate with a size of 12 × 8 × 1 mm3 to more than 7.5 km/s and uniformly drive the aluminum liner with an inner diameter of 6.2 mm and a thickness of 0.4 mm to more than 9.5 km/s. Furthermore, these experiments indicate that CQ-7 is a robust platform for material dynamics and high-pressure physics.