By a News Reporter-Staff News Editor at Defense & Aerospace Week -- Investigators discuss new findings in Propulsion and Power. According to news reporting originating in Ann Arbor, Michigan, by VerticalNews journalists, research stated, "The performance of a radio-frequency plasma thruster is evaluated using a displacement-type, inverted-pendulum thrust stand in the Large Vacuum Test Facility at the University of Michigan. A radio-frequency generator supplies up to 2000 W to the radio-frequency plasma thruster at a fixed frequency of 13.56 MHz."
The news reporters obtained a quote from the research from the University of Michigan, "The matching network is placed inside the vacuum chamber at the thruster, and the radio-frequency power is measured at the matching network input port with a dual-directional coupler. A Faraday probe measures the current density in the far-field exhaust of the thruster, a retarding potential analyzer characterizes the ion voltage distribution, and a Langmuir probe measures the plasma potential. The radio-frequency plasma thruster is operated with argon propellant at mass flow rates of 2.4-7.6 m g/s, at corresponding corrected facility pressures of 1.5 x 10(-6)-4.6 x 10(-6) torr. The maximum thrust observed is 10.8 mN, and the maximum specific impulse is 303 s. Thrust efficiency is below 1% at all conditions. Faraday probe results show that the propellant utilization efficiency is below 15% and that the ionized exhaust has an effective divergence half-angle of 48 deg. Thrust is negatively correlated with the ion beam most probable voltage, showing that retarding potential analyzer results alone may not accurately characterize thruster performance."
According to the news reporters, the research concluded: "Charge-exchange collisions likely have a significant influence on radio-frequency plasma thruster operation."
For more information on this research see: Performance and Probe Measurements of a Radio-Frequency Plasma Thruster. Journal of Propulsion and Power, 2013;29(4):919-929. Journal of Propulsion and Power can be contacted at: Amer Inst Aeronautics Astronautics, 1801 Alexander Bell Drive, Ste 500, Reston, VA 22091-4344, USA.
Our news correspondents report that additional information may be obtained by contacting A. Shabshelowitz, University of Michigan, Dept. of Aerosp Engn, Ann Arbor, MI 48109, United States.
Keywords for this news article include: Michigan, Ann Arbor, United States, Propulsion and Power, North and Central America
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