Hyper Jet Focused-Injection Tapered Capillary Plasma Source Concept

Abstract

The concept of tapered capillary is introduced as a method of injecting focused plasma jet into the breach of bulk-loaded electrothermal-chemical (ETC) launcher. Tapered capillaries will operate in the confined controlled arc regime, and they can provide the advantage of producing focused hyper plasma jets useful for ignition of ETC systems at controlled plasma temperatures and pressures. The concept is also useful for focused implantation of plasma ions on substrates with desired patterns. Such tapered capillaries can inject plasmas at peak kinetic temperatures in the range of 14 000-21 000 K (∼1.2-1.8 eV) and considerable jet pressures of 10-70 MPa for an input discharge current of 20-30 kA over a short pulselength of 100-150 µs. A tapered geometry made of Lexan polycarbonate with 16.8-mm inlet and 8.8-mm outlet radii produces a plasma jet with a plasma temperature of 14 253 K (1.23 eV) at a peak bulk velocity of 4.027 km/s with a 10.38-MPa exit pressure, and a total ablated mass of 10.56 mg. Reducing the tapering to 12.6-mm inlet and 6.6-mm outlet radii produces a plasma jet with a plasma temperature of 16 382-K (1.411 eV) at a bulk velocity of 4.34 km/s and a total of 23.27-mg ablated mass. Further reduction in the tapering to 8.4-mm inlet and 4.4-mm outlet radii produces a plasma jet with a plasma temperature of 20 954 K (1.8 eV) at a bulk velocity of 4.89 km/s with a 70.78-MPa exit pressure, and a total ablated mass of 15.09 mg. The preliminary study shows that the narrow tapering angle produces higher pressure, temperature, velocity, and more ablated mass. Radiant heat flux at the taper exit varies from 2.2 GW/m 2 for the wider tapers to 6.24 GW/m 2 for the narrower ones. Index Terms-Capillary discharge, electrothermal (ET) plasma, tapered hyper jet sources.0093-3813 He has also been a collaborator with teams from the Egyptian Atomic Energy Authority since 1998, collaborating on plasma applications. His current research interests include electrothermal launchers, plasma-matter interaction, plasma coaxial accelerators, plasma pinches, MHD, mathematical modeling, inertial electrostatic confinement, plasma glow discharge, plasma deposition, and surface modification of polymers.

Effect of shock wave formation on propellant ignition in capillary discharge

“…In terms of the effect of capillary discharge plasma on a propellant, Winfrey et al [19][20][21] proposed a novel concept in which the ablation mechanism is forced inside of the open capillary with a propellant liner. The generation of the electrothermal plasma results from radiant heat and Joule heating transport to the liner.…”

Investigation into geometric effect in capillary discharge plasma generator using an improved ablation model

“…However, they assume that the composition of plasma in the capillary is 100% PE, and ignore the effect of electrode ablation. Winfrey et al [16][17][18][19] established an ideal and nonideal plasma model of capillary discharge considering the ablation of wall materials, measured the ablated mass of the capillary liner, and compared the calculated results and experiments. They propose that the ablation mass of PE increases with the discharge current.…”

A Study on the Efficient Method for the Solution of the Saha Equation in the Numerical Simulation of Capillary Discharge

“…In the ET or ETC launch technology, the typical range of temperature and pressure of the plasma generated by capillary discharge are 10000-40000 K and 100 MPa, respectively [10]. At such extreme conditions, plasmas are assumed to be in local thermodynamic equilibrium (LTE) and ablated material is fully dissociated into their elemental constituents and partially or fully ionized [11].…”