An Experiment for Determining the VLF Permittivity of Deep Antarctic Ice

An experiment that has been designed to yield the dielectric and loss properties of the ice cap near Byrd Station, Antarctica, in the very low-frequency range, subsequent to proper interpretation of the input admittance of an electrically short dipole probe, is described. The probe is lowered into a deep drill hole, together with appropriate measuring and telemetering equipment, in order that the parameters of interest may be recorded as functions of vertical depth and frequency. The motivation for such an experiment is discussed and the environmental conditions described, insofar as they restrict the kinds of experimental procedures that can be carried out with reasonable safety and economy. The measurement technique itself is outlined, together with some background material concerning the use of a dipole antenna as a probe for exploring the properties of the medium in which it is immersed. Also discussed is a related experiment performed to provide a check on the method. It involved the use of the same probe and instrumentation to measure the complex permittivity of sawdust, a lossy dielectric material. The results are shown to be in good agreement with those obtained by a more conventional laboratcry method.