A new method of measuring the position of arc spots-optical fibers embedded in the wall of electrodes

Summary form only given. A novel method of measuring the position of arc spots in a tubular arc heater by embedding a large number of optical fibers along the axial direction in the wall of the electrodes has been developed. The light intensity signals from inside the arc heater are transmitted through these fibers and measured by an optical spectrum analyzer. The distribution of light intensity along the axial direction gives an indication of the region in which the arc exists, thus giving the position of the arc spots and its behavior under varying conditions