Measuring the Evolution of Electron Density Profile in a Small Gas-puff z-pinch

Abstract

A three-frame Mach-Zehnder interferometer (TFMZI) was used for taking 3 pictures (5 ns exposure and 13 ns interpicture delay) of the imploding plasma in one z-pinch shot, which provides us a series of interferograms showing the evolution of electron density profile during z-pinch implosion stage. From these interferograms, the electron density profile ne(r , z), the velocities of plasma implosion were derived, and the plasma instabilities appearing as bubbles or fringe shearing were observed clearly. In order to study the correlation between the total energy of x-ray emission and the plasma implosion, thermopiles were also used in the experiments with TFMZI. The results of x-ray radiation diagnostics show us that a near uniform and symmetric imploding plasma shell would emit more x-ray yield than an asymmetric one, which is in good agreement with the implosion dynamics analyses.