Electrodynamic Tether
Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy. Electric potential is generated across a conductive tether by its motion through the Earth's magnetic field.
Read more about Electrodynamic Tether: Tether Propulsion, Uses For ED Tethers, Electrodynamic Tether Fundamentals, Tethers As Generators, Current Collection / Emission For An EDT System: Theory and Technology, Electrodynamic Tether System Fundamentals