Plasma image processing of high speed arc movement in a rail-gun

Decreased electrode erosion is important to maintain an arc and reduce costs. Normally, a vacuum or rare gases such as argon and helium are used to prevent electrode erosion. However, associated equipment and its arrangement are expensive. If the anode attachment of the arc is moving, electrode erosion can be decreased even in an air atmosphere. This paper specifically addresses arc movement, especially the restrike phenomenon, in a rail-gun. The arc length was measured using a plasma image processing on pictures taken with a high-speed video camera. Thereby, the lengths and positions of the arc are determined over time. The average velocity of the anode is as fast as that of the cathode, even in restrike mode.