Schlieren Photography of a Coaxial Accelerator Discharge

The plasma distribution inside a coaxial pulsed accelerator has been examined by use of the schlieren photography technique. The accelerator was filled uniformly with hydrogen at 0.5 mm Hg pressure, and the circuit externally switched. Under these conditions, the current was carried in a roughly paraboloidal shell which was followed by a dense, planar layer of plasma carrying negligible current. Polarity effects were not observed to be strong. The current in the plasma emerging from the muzzle of the acceleration retained its azimuthal symmetry, and was returned to the center electrode by a well-developed pinch on the system axis.