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.

Investigation of a shock wave in an arcjet He plasma by using an electric probe and emission spectroscope

Abstract: We developed an arcjet plasma device having a converging and diverging supersonic conical nozzle. Bright and dark emission structures were formed, depending on the gas pressure in the expansion section. In order to understand the mechanism for the formation of the structures, we evaluated the plasma parameters (electron density and temperature) by using a single probe and a visible emission spectroscope. The analysis of the probe measurements showed no temperature variation around the bright emission region. The plasma density increased significantly by a factor of two. Similar trends were also observed in the spectroscopic measurements. Moreover, the cell width (wavelength) of the shock wave calculated from the compressible fluid dynamics was in good agreement with the experimental value, indicating that this emission structure was caused by a shock cell that could be described by using compressible flow dynamics.

Hollow cathode thrust mechanisms

Abstract: This paper investigates propellant acceleration mechanisms within hollow cathode thrusters based on the results of previous experimental testing. Experiments were conducted on a T5, T6 and ¼ inch cathode. An indirect pendulum micro-thrust-balance was built for the measurement of thrust production in the T5, T6 cathodes while a hemispherical energy analyzer was used for ion energy measurements in the ¼ inch hollow cathode. The data suggest that the thrust mechanism of hollow cathodes is composed primarily of gas dynamic mechanisms, particularly as a result of an intense electron pressure at the cathode exit, and magneto-hydro-dynamic (MHD) forces at high currents and very low flow rates arising from the self-induced azimuthal magnetic field within the orifice. While this initial characterization can only loosely attribute the relative magnitude each mechanism plays it does show evidence for each. Smaller cathodes, such as the T5, operate at lower currents in a more arcjet like mode and show the necessary performance and efficiency to compete with conventional propulsion systems at a mission level.

Unsteady Characteristics of a Quasi-Steady MPD Arcjet Plume

Abstract: The plasma plume of a 1-MW-class quasi-steady magnetoplasmadynamic (MPD) arcjet is studied to reveal the plume plasma fluctuations in a downstream plume region (150–900mm away from the MPD arcjet). By using a double probe and a time-of-flight method, the averaged velocity distribution along the centerline of the plasma plume is found to be almost constant (∼38km/s), and the average ion saturation current is inversely proportional to the square of the distance from the MPD arcjet. The power spectrum density (PSD) of the ion saturation current is proportional to 1/f 1.6 (f : frequency) in 50–200kHz range and it is proportional to 1/f 2.6 above 200kHz. However, fluctuations are dominant in the lower frequency region of 50kHz, where PSD vs. f curve is flat. The spectrum analysis of the fluctuations shows that the MPD arcjet plume in the downstream region is isotropic turbulent flow.

The dependence of diamond growth rate on hydrogen dissociation in a d.c. arcjet plasma

Abstract: A calorimetric technique was used to measure the plasma enthalpy in a d.c. arcjet diamond deposition system. Using these measurements, and a model based on the assumption of local thermal equilibrium (LTE), the temperature of the plasma emerging from the torch nozzle could be calculated. By controlling the electrical power into the torch, the plasma temperature could be varied from 2900 to 4500 K. This range of plasma temperatures corresponded to a fraction of dissociated H2 (α) which ranged from 0.19 to 0.98. Surprisingly, this variation in the concentration of atomic hydrogen had no effect on the diamond growth rate.