Initiation of a discharge channel in water by means of electrical explosion of aluminum foil

This paper reports the results of an experimental investigation into initiation of the electric discharge in service water by means of explosion of aluminum foil having various mass and dimensions. The electric discharge was formed in a chamber with a movable wall (the piston). As an electric energy storage, the capacitor bank having the capacity C = 200–600 μF with charging voltage U ₀ = 2–5 kV (stored energy Q ₀ = 0.4–7.5 kJ) and the rate of rise of the discharging current dI/dt = (3–4) × 10⁹ A/s. The results of experiments showed that destruction (loss of conductivity) of foil occurs at the value of the integral of the current density h _j = (0.3–0.65) × 10⁹ (A²/cm⁴)/s. The stage of the repeated breakdown in the electric discharge occurs when the value of the intensity of the electric field along the discharge channel is of E _rb ≥ 50 V/mm. Geometric dimensions and mass of the initiating conductor that provide the maximum efficiency of conversion of the value of Q ₀ into kinetic energy of the piston have been determined.