Flexible microwave system to measure the electron number density and quantify the communications impact of electric thruster plasma plumes

A microwave interferometer has been implemented that can map the local electron density in two directions, and determine chamber effects such as resonances and multipath through the use of a network analyzer. The same system can be used for communications impact studies by measuring the amplitude and phase of a transmitted signal over a range of frequencies. The system is demonstrated through characterization of a 1 kW arcjet and an SPT-100. The interferometric density measurements of the arcjet mapped the density in a plane orthogonal to the thruster axis and are compared to Langmuir probe measurements. A measurement of the SPT-100 which relates to communications issues is the characterization of the attenuation of signal when transmitted across the plume. The attenuation measurement compares well with a ray tracing simulation using an electron density model of the plume.

Duke Scholars

Author Alec Gallimore Thomas Lord Department of Mechanical Engineering and Materia ...