Simulation Study of the Influence of Experimental Variations on the Structure and Quality of Plasma Liners

TL;DR

This study uses simulations to analyze how experimental variations affect the structure and properties of plasma liners formed by merging plasma jets, providing insights into their sensitivity and robustness.

Contribution

It is the first detailed simulation-based sensitivity analysis of plasma liner structure and global properties to experimental variations in the PLX context.

Findings

Primary shock wave structure is robust to small variations.

Secondary shocks are more sensitive to experimental jitter.

Global properties like Mach number are relatively insensitive.

Abstract

Simulation studies of a section of a spherically imploding plasma liner, formed by the merger of six hypersonic plasma jets, have been performed at conditions relevant to the Plasma Liner Experiment (PLX) [S. C. Hsu et al., IEEE Trans. Plasma Sci.~{\bf 46}, 1951 (2018)]. The main aim of simulations was the sensitivity study of the detailed structure of plasma liners and their global properties to experimental mass variations and timing jitter across the six plasma jets. Experimentally observable synthetic quantities have been computed using simulation data and compared with the available experimental data. Simulations predicted that the primary oblique shock wave structure is preserved at small experimental variations. At later phases of the liner implosion, primary shocks and, especially, secondary shocks are more sensitive to experimental variations. These conclusions follow from the simulation data as well as comparisons between synthetic and experimental interferometry and visible images. Small displacements of the shock wave structures may cause significant changes in the synthetic interferometer data at early time. Our studies also showed that the global properties of the plasma liners (averaged Mach number and averaged ram pressure along leading edges of plasma liners) are not very sensitive to experimental variations. Simulation data of the liner structure were largely confirmed by the PLX experimental data.