Transient plasma sheath model for thin conductors excited by negative highvoltages with application to electrodynamic tethers

The electrodynamic tether is a powerful new tool for in-space propulsion an d in situ ionospheric research, To full?; exploit its potential, know ledge of both its steady-state and transient electrical responses is needed. The tether's transient response is governed by the interaction of the tether a nd its endpoints with the surrounding ionospheric plasma. Presented here is an improved model of the plasma-tether interaction that accounts for high- induced voltages and a dynamic nonlinear sheath. In this work, the model fo r the plasma-tether system was developed analytically and verified via part icle-in-cell simulations and through experimental data. The model is valid in the temporal regime between the ion and electron plasma periods, and for large negative applied voltages. The model is based on an ion-matrix-sheat h that is a function of applied voltage,Although the investigation was gear ed toward electrodynamic tethers, it also has application to other areas of research that employ the dynamic nature of the plasma sheath.