Electrode Attachment of DC Free Arc Between a Pair of Parallel Conductors in Argon and Nitrogen

Summary form only given. The decrease of electrode erosion is important to keep the arc and to save the cost. Normally, the vacuum or rare gases such as argon and helium are used to prevent the electrode erosion. If the anode attachment of arc is moving, the decrease of electrode erosion could be achieved even if atmosphere is air. In this paper, the arc movement in rail-gun. especially restrike phenomena was measured by using high speed video camera. There are two electrodes made of copper, and the arc is generated between them in argon and nitrogen. The current is 200 A at the start point, and it decreases with the position of the arc to the end of electrodes. It is almost constant about 100 A near the end of electrodes. The gap distance between the electrodes is 10 mm and the length of electrodes is 300 mm. The arc mode is changing with the time and each pictures. Normally, the cathode spot is moving first, and then the anode spot is moving with a re-strike mode. The arc column is very flexible and the arc length becomes changeable. Before the anode spot becomes the re-strike mode, the arc length gradually increases. However, after the anode spot reached the re-strike mode, the arc length suddenly decreases. In this situation, the arc length becomes near electrode distance.