Thermodynamics effects on the compression dynamics of soft x-ray emission in plasma focus

Abstract

In a plasma focus operation, the X-ray radiation properties are dependent on the thermodynamics data such as ion fraction (α), effective ion charge number (Zeff), and effective specific heat ratio (γ) at different temperatures. In Corona Model (CM), the value of ion fraction was first obtained from McWhirter’s equation and was subsequently used in determining the Zeff and γ values. The state-of-the-art ion fraction calculation based on Mazzotta’s (Mazz) in Modified Corona Model (MOCM) was compared with McWhirter’s (McW) computations for neon, argon and nitrogen gases. The implementation of McW’s and Mazz’s ion fraction calculation in CM and MOCM cases respectively showed deviations in terms of temperatures. The aim of this study is to investigate the Zeff and γ values based on the ion fraction values determined from Mazz’s and McW’s computations and applied in numerical experiment of plasma focus device emphasizing on radial compression plasma dynamics and parameters of soft X-ray (SXR) emission. The Zeff and γ for both computations were incorporated in Lee code for numerical experiment on SXR yield. Lee code version RADPF5.15K has been used with the incorporation of Zeff and γ computation based on CM and MOCM operating in various gas pressures. The parameters of SXR yield played important role as they were affected by these different thermodynamics data calculation used in CM and MOCM in the Lee Model. Among these three operating gases, argon plasma of MOCM showed tremendous significant effect towards the results in SXR yield which cannot be disregarded. Thus, it is concluded that the ion fraction values derived from Mazz’s computation has a significant effects on Zeff, γ, higher SXR yield and enhances radial compression phase performance.