Impedance measurements on a VLF multiturn loop antenna in a space plasma simulation chamber

The Space Sciences Laboratory of The Aerospace Corporation is presently defining an experiment to test a loop antenna configuration for a VLF transmitter in the ionosphere. The primary objectives of the experiment are to validate existing models for radiation by a loop antenna and to study the performance of the antenna in the ionospheric plasma. A one‐third scale model of the antenna has been constructed. Impedance measurements have been made on the model in a 5‐m diameter space plasma simulation chamber at NASA Lewis Research Center. The measurements confirm that the reactance of the antenna in an ionospheric plasma is essentially identical to its free space self‐inductance. The effective series resistance of the circuit increases with frequency. The losses are attributed to power transferred to plasma turbulence.