Research On Laser-driven Flyer Ignition Design Technology

The safety and reliability design of fire-set system act as an extraordinarily import role of the development of the weapon systems. Due to its unique firing energy, the laser driven flyer ignition mode is considered to be one of important ways of future safe ignition modes.The design of laser driven flyer ignition are studied systemically and deeply from many sides of mechanism analysis, theoretical computation and experiment validation.According to the objective and requirement of ignition system, the general design schemes of laser driven flyer ignition system are put forward. The functions and performance of each key component are determined. The approaches and directions of miniaturization and engineering from the systemic side are put forward.Based on deep understanding of laser-metal target interaction mechanism and deail analysis of developing behaviors with time and space of laser supported detonation wave(LSDW), a laser-target coupling dynam module has been build up. Taking aluminum flyer for instance, the calculational formula of the flyer characteristic parameters including momentum, velocity, kinetic energy, energy utilization, optimal accelerate distance and proportion rush energy have been deducted. And the influences of laser parameters (power density, pulse width and focus diameter) and flyer structure parameters (semi-diameter and thickness) on characteristic parameters metioned above have been discussed. In order to abtain a further understanding of the flyer formation process, the ablation of laser on the film, the flyer formation threshold as well as flyer integrity, which are three main elements of the intact flyer formation, are discussed. The ablation depth of aluminum, copper and magnesium films radiated by pulsed laser are worked out theoretically. The relationship between laser power density, pulse width and the ablation depth on three kind films is especially analyzed. The experimental researches on aluminum film have been accordingly developed. The thresholds of laser energy density and power density for the formation of three kind flyers have been theoretically computed. Then the influences of laser pulse width on the threshold have been discussed. The factors affecting flyer integrity have been briefly analyzed. And the experiments to evaluate flyer integrity have been performanced.Flyer planarity and average velocity have been tested by optical fibre detector array test system under the conditons of different laser input energy and different flyer construction. The results show that:under the same condtion, the compound flyer performances including flyer planarity, average velocity and energy utilization are better than those of the single layer flyer. The thickness of the insulated layer of Al2O3 has minor affection on compound flyer planarity, while it has some affection on compound flyer velocity and energy utilization. The compound flyer which contains a thicker insulated layer may abtain higher velocity and energy utilization.