Ionospheric experiment with a low work function tether loop

An entirely passive and free of consumable ionospheric experiment, based on a low work function tether (LWT) loop with a control unit equipped with some basics sensors at its center, is presented. The loop has a torus shape and a hollow cross-section. It is made of an aluminum substrate coated with a low work function material to stimulate electron emission through thermionic and photoelectric effects. The work presents an electrodynamic model for the experiment and studies the current and voltage profiles developed in the anodic and cathodic segments of the LWT due to the motional electric field. Two modes of operation, with and without switches in the loop to interrupt the electric current, are considered. It is shown that the loop is deorbited by the Lorentz force exerted by the ambient magnetic field on the electric current. An analysis of the attitude dynamics in the presence of the gravity gradient and the Lorentz torques reveals that, for a circular equatorial orbit, the position of the loop with its symmetry axis normal to the orbital plane can be spin-stabilized easily. The required instruments and the scientific information that would be provided by the experiment are discussed.

Ionospheric experiment with a low work function tether loop Articles