Relativistic electron beam injection from spacecraft: Performance and applications

Linear accelerators (linacs), producing relativistic (5 MeV) electron beams are down to a size that allows them to be flown on spacecraft and sounding rockets. This opens up to new opportunities for atmospheric/ionospheric modification experiments where the mesosphere and lower thermosphere regions can be perturbed down to 40 km altitude. In this presentation, the relativistic electron beam injection process is investigated by means of 3-dimensional particle-in-cell (PIC) simulations to determine the initial interaction of the beam with the spacecraft and the ambient plasma. The results indicate, that relativistic beams are more stable than keV-energy beams investigated in the past, allowing the injection and propagation of beams with currents several orders of magnitude higher than for keV-energy beams. The superior stability of relativistic beams allows a large fraction of the energy to be deposited in the lower atmosphere. It is suggested that relativistic beams can be applied to investigations of atmospheric electrical and chemical processes.