E-Beam Propagation And Interaction With The Atmosphere.

Abstract

This study purports to investigate whether a conductive tether left uninsulated and
electrically floating in LEO could serve as an effective e-beam source to produce artificial
auroras. An electrically floating tether comes out biased highly negative over most of its
length. Ambient ions impacting it with KeV energies liberate secondary electrons, which are
locally accelerated through the 2D tether voltage-bias, race down magnetic lines, and result
in peak auroral emissions at about 120-160 km altitude. Since no current flows at either
tether end, a bare-tether e-beam is fully free of spacecraft charging problems. Beam
propagation and beam-atmosphere interactions need be modelled in a simple but quantitative
way so as to allow a satisfactory discussion of observational options and their feasibility. The
evolution in the energy spectrum of secondary electrons, their pitch distribution, and beam
broadening due to collisions with neutrals, which would result in a broader but weaker tether
footprint in the E-layer, need be modelled. Relations between