Laser Accelerated Plasma Propulsion System (LAPPS)

Recently conducted experiments at the University of Michigan and elsewhere have shown that ultrashort pulse (ultrafast) lasers could accelerate charged particles to relativistic speeds. For example a picosecond laser pulse with only one joule of energy can accelerate an electron to MeV energy in just a few microns distance. This takes place through the high gradient potential that manifests itself in an electric field of a gigavolt per cm which in turn accelerates the electron to a megavolt energy over a distance of 10 microns. Current achievable laser peak power of 10 watts has been utilized in the study of relativistic non-linear optics in plasmas, and it is expected that laser power values will be reached in the near future that will accelerate protons to energies equal to their rest mass energy. That readily means that when such particles are ejected from a system at 0.866 the speed of light they will produce a specific impulse of 26 million seconds. Current experiments have also demonstrated that a beam of one MeV protons containing more than 10 particles has been accelerated by an electric field of 10 GeV/cm corresponding to a laser power of about 100 TW. On the basis of these accomplishments it is reasonable to project that accelerating 100 MeV proton beams containing 10 particles will be quite achievable in the near future. If utilized as a propulsion device such a system will make distant planets in the solar system and some Copyright © 2001 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. interstellar missions reachable in relatively short times.