AVS 52nd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS-FrM

Paper PS-FrM8
Investigating the Interaction of High-Pressure, High Temperature Plasmas with Propellant Surfaces through Experimental Modeling

Friday, November 4, 2005, 10:40 am, Room 302

Session: Plasma Surface Interactions III
Presenter: R. Blumenthal, Auburn University
Authors: R. Valliere, Auburn University
A. Dyachenko, Auburn University
R. Blumenthal, Auburn University
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The electrothermal chemical (ETC) ignition of propellants has many advantages over conventional ignition, the most remarkable is a short, highly-reproducible ignition delay. ETC ignition results from the impingement of a multi-millisecond long pulse of high-pressure, high-density atomic plasma on the surface of the propellant. The plasma is generated by the nearly complete ablation of a polymer tube as a large capacitor is discharged through it. Direct determination of the chemical and physical processes responsible for the beneficial properties of ETC ignition would require surface sensitive probes capable of penetrating a plasma pulse that has pressures up to 33 MPa and temperatures as high as 30,000 K.@footnote 1@ In the absence of suitable probes, one must find an alternative approach. An often overlooked alternative to direct measurement is experimental modeling, pioneered by Winters and Coburn.@footnote 2@ Experimental modeling consists of replacing a complex and/or impenetrable environment with one or more of its individual components, generated in a way that is compatible with traditional surface probes. In the study of plasma ignition, the challenge is to find a vacuum compatible replacement for the ETC source output. In this work, atomic plasmas with composition and pressures close to those of the plasma pulse are created by laser ablation of thin polymer films deposited directly on the surface of the propellant. The chemical products of the nanosecond-long plasma with the propellant surface are monitored by mass spectrometry and the resulting surface is examined by XPS and Auger with the results compared to those found after truncated ETC ignition. @FootnoteText@ @footnote 1@ M. Nusca, M.J. McQuaid and W.R. Anderson, J. Thermophys. Heat Trans. @bold 16(1)@,157 (2002).@footnote 2@ H.F. Winters, and J.W. Coburn, JVSTB @bold 3(5)@, 1376 (1985).