Efficiency of Conversion of the Magnetic Energy into Z-Pinch Radiation of Nested Arrays of Mixed Composition at the Angara-5-1 Facility

Abstract

The results of experiments on the study of the generation of high-power pulsed soft X-ray (SXR) emission with a photon energy higher than 100 eV (in the spectral range with wavelengths λ shorter than 120 Å) during the plasma implosion of nested arrays of mixed composition with different ratios of array radii carried out on a pulse power facility Angara-5-1 with a discharge current level of up to 3.5 MA are presented. The outer array consisted of fibers of a substance with a low atomic number (plastic), and the inner array consisted of a substance with a high atomic number (tungsten, W). In the case of nested arrays of this design, a significant increase in the peak SXR power was obtained compared to single tungsten arrays with the same parameters as for the tungsten array in the inner array. By optimizing the linear mass of the outer array and the ratio of array radii, powerful SXR pulses were prepared with a high pulse power up to 18 TW, pulse energy of ~140 kJ and short pulse duration of ~5 ns. It is shown that by optimizing the linear mass of the outer array (fiber array) it is possible to achieve ~90% conversion of the electromagnetic energy pumped into the vicinity of the array into X-ray emission pinch energy. In this case, the fraction of the kinetic energy of the plasma implosion into the emission energy is not higher than 30%. In shots optimal over the output SXR power, an increase in the fraction of the X-ray emission energy in the spectral range of λ ∈ (30, 40) Å was recorded that is 30–100% than that in single tungsten arrays with similar parameters.