Plasma spectroscopy in a self collapse process

  Yoav Priel  ,  Tal Queller  ,  Yitzhak Maron   
Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Israel

Z-pinch machines were originally developed for thermonuclear fusion. Plasma is a state of matter where the gas particles are electrically charged. Plasma is made of atoms, ions, and nuclei. When two heavy particles interact, nuclear fusion may occur. Nuclear fusion is when ions fuse into one new ion, lighter than both the original particles together, releasing energy. The utilization of this energy can lead to energetic abundance [1].

The goal of my study was to find the plasma dynamics through the self collapse of an Oxygen plasma column, and the dynamics of the current in the plasma. I measured the distribution of the current in the plasma through time. The study included laboratory experiment. In our experiment, the WIS Z-pinch machine was used [2]. The current distribution was found by measuring the magnetic field at the various radii. The experimental results showed that half of the total current in the plasma was in radiuses between four to six millimeters. In contrast to what was expected, at the center of the plasma cylinder, there was hardly any current flowing (<10% of the total). The current distribution declined steeply to zero in the cylinder's center. Concluding that half of the current was flowing outside the main plasma column, while half flowed in bigger radii. This current passed through the dilute plasma that was "left behind", while most of the plasma collapsed.

This measurement of the current's distribution is first of its kind in this type of plasma. The measurement adds important knowledge to the scientific understanding of the self collapse process. Those results may influence future research in the effort to achieve controlled nuclear fusion and provide the world with clean energy [3].

[1]     D.D. Ryutov, M.S. Derzon and M.K. Matzen, “The physics of fast z pinches”, Rev. Mod. Phys. 72 (2000) 167.

[2]     Rosenzweig, G., Kroupp, E., Fisher, A., and Maron, Y. “Measurements of the spatial magnetic field distribution in a z-pinch plasma throughout the stagnation process”, JINST 12, (2017) 09004.

[3]     ] J.L. Giuliani and R.J. Commisso, “A review of the gas-puff z-pinch as an X-ray and neutron source”, IEEE Trans. Plasma Sci. 43 (2015) 2385.