Investigation of anode and cathode jets influence on electric arc properties with current up to 500 kA

A number of phenomena connected with the formation of electrode jets in discharges in hydrogen at a current of 10⁵-10⁶ A, a current growth rate of 10¹⁰ A/s, an initial pressure 0.1-4.0 MPa, and a discharge gap length of 5-40 mm were studied. After the secondary breakdown, the jets are observed through a discharge semitransparent channel, widening with velocity (4-7) · 10² m/s. Shockwave formation was detected at the interaction of jets with the surrounding gas and the opposite electrode. Plasma vapor pressure of metal near the end of the tungsten cathode 70 μs after initiation of a discharge was 180 MPa. Thus, magnitude of brightness temperature was 59 · 10³ K, with an average charge of ions-m~=3.1, and a concentration of metal vapors n=5.3·10¹⁹ cm^-3. While those at the end of the anode 90 μs after initiation of discharge: m~=2.6, n=7.4·10¹⁹ cm^-3. Probable reasons of high-voltage drops near the electrodes (the summarized magnitude of which is ∼1 kV) are discussed on the basis of experimental data. For the first time, the shadow method registered symmetric ejection of material from the all-cathode surface the maximum discharge current was observed.