On the Generation of Plasma Jets in the Kilojoule Plasma Focus Device

Laser-optic methods were used to study the properties of plasma jets generated in the KJ Plasma Focus device. Measurements of the plasma jet velocity were conducted immediately after its appearance. During the first 10 ns, the average velocity is about 5 X 10(7) cm/s, which corresponds to energy of 18 keV for the ions of nitrogen, which was the working gas of the PF setup. The jet density and velocity decrease manifold over distance of 2-3 cm from its generation point. The experiments confirm that the main reason of jet generation is the necking of the pinch. It was found that after the pinch decay, a new plasma column appears, which propagates in the axial direction.