MAGNETIC FIELD MEASUREMENTS IN A CYLINDRICAL PINCH TUBE

Magnetic field measurements in a cylindrical linear pinch tube with probes are described. Tests are performed with a discharge current frequency of 20 kilocycles in nitrogen at an initial pressure of 0.1 mm Hg. Initial capacitor voltage is varied from 1000 to 5000 volts. The magnetic field distribution, the radial current distribution, and the current density in the pinch tube are described. The discharges are concluded to be symmetric above 2000 volts. The symmetric discharges have distinct characteristics. At the start of the discharge, current flows near the outer periphery of the pinch tube. A portion of the current concentrates in a thin shell which moves toward the axis at a high velocity. The remainder of the current flows between the rapidly advancing shell and the outer radius of the pinch tube. After the formation of the first shell a second shell may form and move toward the axis. (auth)