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Antiproton powered propulsion with magnetically confined plasma enginesMatter-antimatter annihilation releases more energy per unit mass than any other method of energy production, making it an attractive energy source for spacecraft propulsion. In the magnetically confined plasma engine, antiproton beams are injected axially into a pulsed magnetic mirror system, where they annihilate with an initially neutral hydrogen gas. The resulting charged annihilation products transfer energy to the hydrogen propellant, which is then exhausted through one end of the pulsed mirror system to provide thrust. The calculated energy transfer efficiencies for a low number density (10(14)/cu cm) hydrogen propellant are insufficient to warrant operating the engine in this mode. Efficiencies are improved using moderate propellant number densities (10(16)/cu cm), but the energy transferred to the plasma in a realistic magnetic mirror system is generally limited to less than 2 percent of the initial proton-antiproton annihilation energy. The energy transfer efficiencies are highest for high number density (10(18)/cu cm) propellants, but plasma temperatures are reduced by excessive radiation losses. Low to moderate thrust over a wide range of specific impulse can be generated with moderate propellant number densities, while higher thrust but lower specific impulse may be generated using high propellant number densities. Significant mass will be required to shield the superconducting magnet coils from the high energy gamma radiation emitted by neutral pion decay. The mass of such a radiation shield may dominate the total engine mass, and could severely diminish the performance of antiproton powered engines which utilize magnetic confinement. The problem is compounded in the antiproton powered plasma engine, where lower energy plasma bremsstrahlung radiation may cause shield surface ablation and degradation.
Document ID
19890018329
Document Type
Conference Paper
Authors
Lapointe, Michael R. (Sverdrup Technology, Inc. Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1989
Subject Category
SPACECRAFT PROPULSION AND POWER
Report/Patent Number
NASA-CR-185131
NAS 1.26:185131
E-5025
AIAA PAPER 89-2334
Meeting Information
Joint Propulsion Conference(Monterey, CA)
Funding Number(s)
CONTRACT_GRANT: NAS3-25266
PROJECT: RTOP 506-42-41
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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