Rule of the pulse energy from ground-based lasers for the laser ablation propulsion in space.

For the laser ablation propulsion in space, the rule of the pulse energy from ground-based lasers is studied, in which both the complex beam propagation effects in the turbulent atmosphere of a real-world scenario and the momentum coupling of laser-matter interaction in space are considered. The analytical propagation formulae of laser beams in the turbulent atmosphere along a slant path are derived, and the fitting formula of optimized pulse width is obtained. In particular, the analytical rule of the pulse energy from ground-based lasers to reach the threshold and optimal momentum coupling of laser-matter interaction is derived. It is necessary to increase the laser altitude in order to reach the threshold momentum coupling of laser-matter interaction in space. Furthermore, by ground-based lasers, the several nanoseconds pulse width at the target (e.g., around 1 ns) may be suitable for the laser ablation propulsion, and the removal of the centimeter-scale space debris is much more suitable than the meter-scale one.