Multi-chord fiber-coupled interferometry of supersonic plasma jets and comparisons with synthetic data

Abstract

A multi-chord fiber-coupled interferometer [Merritt et al., Rev. Sci. Instrum. 83, 033506 (2012)] is being used to make time-resolved density measurements of supersonic argon plasma jets on the Plasma Liner Experiment [Hsu et al., Bull. Amer. Phys. Soc. 56, 307 (2011)]. The long coherence length of the laser (>10 m) allows signal and reference path lengths to be mismatched by many meters without signal degradation, making for a greatly simplified optical layout. Measured interferometry phase shifts are consistent with a partially ionized plasma in which an initially positive phase shift becomes negative when the ionization fraction drops below a certain threshold. In this case, both free electrons and bound electrons in ions and neutral atoms contribute to the index of refraction. This paper illustrates how the interferometry data, aided by numerical modeling, are used to derive total jet density, jet propagation velocity (~15-50 km/s), jet length (~20-100 cm), and 3D expansion.

arXiv comment6 pages, 4 figures, invited paper at the 19th High Temperature Plasma Diagnostics Conference, Monterey, CA, May 6--10, 2012

References in corpus (2)

• One-dimensional radiation-hydrodynamic scaling studies of imploding spherical plasma liners
• Multi-chord fiber-coupled interferometer with a long coherence length laser

Cited by in corpus (10)

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• Experiment to Form and Characterize a Section of a Spherically Imploding Plasma Liner
• Laboratory plasma physics experiments using merging supersonic plasma jets
• Experimental characterization of a transition from collisionless to collisional interaction between head-on-merging supersonic plasma jets
• Experimental characterization of a section of a spherically imploding plasma liner formed by merging hypersonic plasma jets
• Observation of Rayleigh-Taylor-Instability Evolution in a Plasma with Magnetic and Viscous Effects
• Experimental Measurements of Ion Diffusion Coefficients and Heating in a Multi-Ion-Species Plasma Shock
• Observation of Shock-Front Separation in Multi-Ion-Species Collisional Plasma Shocks