Arcjet rocket

About: Arcjet rocket is a research topic. Over the lifetime, 1121 publications have been published within this topic receiving 9687 citations. The topic is also known as: Arcjet.

Characterization of a Large-Scale Arcjet Facility Using Tunable Diode Laser Absorption Spectroscopy

Abstract: A laser-based sensor was developed and deployed for in situ monitoring of the gas temperature in the plenum after the arc heater and before the expansion nozzle in the 60 MW interaction heating fac...

Langmuir probe measurements of an arcjet exhaust

Abstract: Electrostatic (Langmuir) probes of both spherical and cylindrical geometry have been used to obtain electron number density and temperature in the exhaust of a laboratory arcjet. The arcjet thruster operated on nitrogen and hydrogen mixtures to simulate fully decomposed hydrazine in a vacuum environment with background pressures less than 0.05 Pa. The exhaust appears to be only slightly ionized (less than 1%) with local plasma potentials near facility ground. The current-voltage characteristics of the Langmuir probes indicate a Maxwellian temperature distribution. A spherical probe, located approximately 30 cm downstream of the thruster exit, obtained electron number densities on the order of 1 to 3 x 10 9/cm3 at temperatures between 0.4 and 0.7 eV. The measured electron number density decreased exponentially off centerline while the values of the electron temperature remained relatively constant. Nomenclature A = probe surface area, m2 A' = wetted surface area of spherical probe (2nR2r), m2 Ae = nozzle exit area, m2 A* = nozzle throat area, m2 D = probe diameter, m e = electron charge, C G — arc gap setting, m / = current, A I0 — electron saturation current, A k = Boltzmann constant, J/K L — length, m / = cylindrical probe length, m M — neutral mass, kg m = charged specie mass, kg n = number density, particles/m3 R = radius, m T = temperature, K V = voltage or potential, V A = mean free path, m AD = Debye length, m (p = nozzle half angle, deg Superscripts a = arc Subscripts c = constrictor e = electron / = floating / = ion n = neutral particles p = probe oo = plasma

Density measurements in a DC arcjet using scanned beam deflection tomography

Abstract: We have demonstrated a scanned beam deflection technique, and applied this technique to imaging the free stream of a dc arcjet plasma plume. An acousto-optic deflector sweeps a HeNe beam transverse to the jet flow direction. A transform lens and split photodiode measure angular beam deflections produced by refractive index gradients in the arcjet plume. Line scans of beam deflection angle are collected at a 1 kHz sweep rate. Assuming axial symmetry, tomographic reconstruction is used convert the beam deflection data to refractive index. Multiple one-dimensional scans are stacked to produce two-dimensional refractive index images. Index of refraction is directly related to density for measurements in pure argon. Good images are obtained at chamber pressures as low as 4 Torr.Measurements were performed using both pure argon and argon/ hydrogen/methane mixtures in the arcjet reactor at a variety of reactor chamber pressures including conditions for diamond deposition. We found significant differences in the radial transport with chamber pressure and with feedstock composition. Comparison of index of refraction data with photographs of arcjet optical emission shows that the emission is not a good representation of the jet density. The simplicity and sensitivity of the scanned beam deflection technique may allow its use for process control when using arcjets for plasma deposition of material.

Experimental Simulation of Magnetic Sails

Abstract: In order to simulate the interaction between the artificially deployed magnetic field produced around a magnetic sail spacecraft and the solar wind, a laboratory simulator in a space chamber was designed. As a solar wind simulator, a high-power magnetoplasmadynamic arcjet was operated in a quasisteady mode of about 0.8 ms duration to provide a high-speed hydrogen plasma plume of about 0.7 m in diameter, which is accelerated to above 20 km/s with high plasma densities around 10 17 -10 19 m -3 . Into this high- density and high-velocity plasma jet, a small coil of 2-cm-diameter was immersed to obtain 1.9-T magnetic field at the center of the coil. These devices are operation in a large 2-m- diameter space chamber, and the formation of a magnetic cavity was observed around the coil. From the analysis of scaling parameters, it is found that the laboratory experiment of the plasma flow around the coil of the magnetic sail corresponds to a sub-Newton-class magnetic sail.