Photographic Studies of Electric Explosion of Thin Metal Films

The paper represents the experimental studies of slow (with a characteristic process time ≈ 50÷100 μs) electric explosion of thin metal films (Cu or Ti) on silica substrates. The films (with the thickness ≈ 40 nm) are manufactured with magnetron sputtering. Waveforms of current and voltage of the explosion are recorded. The first current maximum was up to 2.04 kA. Energy input in the films was 6.6÷13.8 J. Schlieren visualization and direct photography are used for studying the process of explosion of the films and their expansion into a free space. The structure of generated gas dynamic flows is visualized and characterized. Main features of spatiotemporal dynamics of plasma region and resulting shock waves are established. The inner structure of explosions had a complex formation due to the fusion of plasma discharges and shocks at the early stages of the process ( ≈ 5 μs). In addition, (> 10 μs) a classical structure (a quasi flat shock wave, expanding plasma etc.) of the plasma explosion of thin films is established. The parameters of a generated weak shock are estimated.