Influence of the cathode and anode jets on the properties of a high-current electric arc

A study is made of the effects related to the formation of electrode jets in discharges in hydrogen and air at a current of 10(5)-10(6) A, a current growth rate of 10(10) A/s, an initial pressure of 0.1-4.0 MPa, and a discharge gap length of 5-40 mm. After secondary breakdown, jets are observed in a semitransparent discharge channel expanding with a velocity of (4-7) x 10(2) m/s. The formation of shock waves in the interaction of the jets with the ambient gas and the opposite electrode is observed by the shadowgraphy method. Seventy microseconds after the beginning of the discharge, the pressure of the metal vapor plasma near the end of the tungsten cathode amounts to 177 MPa. The brightness temperature in this case is T = 59 x 10(3) K, the average ion charge number is (m) over bar = 3.1, and the metal vapor density is n = 5.3 x 10(19) cm(-3). After 90 mus, the average ion charge number and the metal vapor density near the anode end are (m) over bar = 2.6 and n = 7.4 x 10(19) cm(-3), respectively. Based on the experimental data, possible reasons for the abnormally high values of the total voltage drop near the electrodes (up to similar to1 kV) are discussed. (C) 2002 MAIK "Nauka/Interperiodica".