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Performance of a 100 kY class, applied field ?IPD thruster was evaluated and sensitivities of discharge characteristics to arc current, mass flow rate, and applied magnetic field were investigated. Thermal efficiencies as high as 60%. thrust efficiencies up to 218, and specific impulses of up to 1150 s were attained with argon propellant. Thrust levels up to 2.5 N were directly measured with an inverted pendulum thrust stand at discharge input powers up to 57 kY. It was observed that thrust increased monotonically with the product of arc current and magnet current.

Infrastructure safety and security is a growing area of engineering analysis. Dams and levees need to be considered as part of these critical infrastructure assessments. In the United States alone, there are over 80,000 dams and 100,000 miles of levees. Over 26,000 of these dams are classified as high or significant hazard. A study has recently been undertaken with the goal of expanding blast security assessments for modeling the impacts of explosions to include analysis of embankment dams and levees. Specific aims of the study include developing reasonably accurate models to assess localized, shallow impacts and developing methods to assess global stability impacts. Assessing these structures requires a unique combination of understating of blast impacts, soil modelling under high energy dynamic loading, embankment dam failure modes, and conventional geotechnical slope stability. A trial dam section was developed and possible failure mechanisms due to blast impacts were determined. Published numerical soil models, developed and validated for land mine analyses, were evaluated with regard to typical soil properties of embankment dam materials. An applicable soil model was selected, and the numerical trial dam model was analysed for an explosion on the crest. The results were assessed using conventional geotechnical engineering software and engineering judgment. A step-by-step procedure for assessing the impacts of explosions on embankment dams has been developed, and a simplified chart for assessing localized breach potential have been developed. Areas for further study and validation are also identified. The work combines research from military applications with state-of-the-art infrastructure security analyses and conventional geotechnical engineering evaluations.

Performance and lifetime requirements for multimegawatt magnetoplasmadynamic (MPD) thrusters were used to establish a baseline 2.5 MW thruster design. The chamber surface power deposition resulting from current conduction, plasma and surface radiation, and conduction from the hot plasma was then evaluated to establish the feasibility of thruster operation.It was determined that state-of-art lithium heat pipes were adequate to cool the anode electrode, and that the liquid hydrogen propellant could be used to cool the applied-field magnet, cathode, and backplate.Unresolved issues having an impact on thruster design are discussed to help focus future research.