Research Magnetically Driven Flyer Hypervelocity Launch

The technique of magnetically driven hyper-velocity flyer launching is a new experimental method and tool developed in last decade, and it is widely applied in the fields of dynamic high pressure physics, shock dynamics and high energy density physics. The magnetically driven quasi-isentropic loading, which lies between the shock and quasi-static for compression, compress the sample to high pressures with a process of nearly isentropic. The isentropic compression is also a link between the shock and isotherm compression experiments. The technique of magnetically driven flyer plates is another capability of magnetically driven loading. For the present, the flyer plates have been accelerated to hypervelocity about45km/s by using this technique, which is the highest value at the laboratories for humans.In this paper, the significance and advances on the techniques of magnetically driven flyer plates were described. Base on the magnetically driven isentropic loading generator CQ-4,the physics process of magnetically driven flyer was studied systematically in experiments and simulations. The macro-size metal flyer plate was accelerated to hypervelocity15.2km/s by using. preliminary optimizations of the electrode panel configurations. This article has a certain practicability and reference value for studying high-velocity impact problems, such as space debris shield and equation of state (EOS) of materials.The main research work and results in this paper are as follows:1. An electrical circuit calculation procedure with variable parameters was programmed with FORTRON language according to the equivalent circuit of apparatus CQ-4. Combining circuit calculation program with LS-DYNA980-EM, a method coupled with electrical circuit equations was proposed to simulate the process of magnetically driven flyer, which is an important foundation for designing and optimizing magnetically driven experiments.2. The panel structure for hypervelocity flyer plates were discussed and optimized by calculation and simulation using LS-DYNA980-EM. The optimized design results are that the design of the electrode panels with "Notch" and "ear" is better to make magnetic field distributing uniformly along the length of panel, and that "bore" is used to reduce the side edge deformation of panel. At the same time, it is advantageous to reduce the inductance and resistance of load by shortening the length of electrode panels as soon as possible and strengthening the panels to reduce the deformation.3. Experiments of magnetically driven flyer plates were conducted on CQ-4, and the aluminum flyer with the initial-dimension of Φ5×0.35mm was launched to15.2km/s. An aluminum flyer with the initial.dimension of Φ5×0.35mm is accelerated to about10.7km/s before loss of signals by measuring the free surface velocity profile. The flatness of flyer plates was measured by optical fiber pin array, and the effective thickness of flyer was obtained from symmetrical collision experiments. A new experimental technique of magnetically driven flyer is established to research hypervelocity impact phenomena and shock compression of materials in the field of shock dynamics. The experimental results testified the optimization design of panel structure for hypervelocity flyer plates launch on CQ-4.The experimental results show that the flatness is less than11ns when the flyer with initial size of12x9.2x0.73mm was accelerated to velocity of6.5km/s and distance of4.3mm, and that the effective thickness of the aluminum flyer is about0.447mm.