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In order to get a clearer view of a wire explosion through use of oscillographic recording and Schlieren high-speed photography, experiments were performed with medium energy input which show all the stages of the wire explosion. Oscillographic recordings display four of the distinct stages of the wire explosion including the heating stage, explosion, current dwell, and the reignition stage. The Schlieren-framing photographs show the cylindrical symmetry of the contact surface, primary shockwave, arc channel, and the secondary shockwave. The Schlieren-streak photography yielded the trajectory curves of the contact surface and of the shockwaves from the beginning of the explosion stage to the end of the restrike stage. Photographs with a strong illumination reveal the clear view of the unexploded core residue. The experimental results obtained during the explosion stage follow the predictions of the "metal explosion model".1 By taking oscillographic traces of current and voltage during wire explosions with variation of the initial discharge voltage, a converging value of the explosion time at the high voltage limit is obtained. The steady state supercritical ex-plosion speed is then determined by dividing the wire radius by the limiting explosion time, and found to be 350 m/sec for aluminum. There exist two distinct exponential relations between the dwell time and the dwell voltage. The more rapid exponential decay of dwell time with dwell voltage in the lower voltage region is attributed to the interruption of the development of the arc discharge chan-nal along the central line of the cloud of product particles by the debris of unexploded core residue. For explosions free from unexploded core residue, empirical relations between the speed of shocks and the specific energy of product above the heat of explosion are found. The primary shock speed is found to be proportional to the square-root of the specific energy of the explosion product. The speed of the secondary shock which is generated by the arc discharge through the explosion product is found to be less sensitive and proportional to the cube-root of the specific energy of the arc discharge product.
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