Beam-Riding of a Parabolic Laser Lightcraft

Abstract

The impulse coupling characteristics of a parabolic laser-driven thruster (‘lightcraft’) are investigated in free flight experiments using a pulsed CO2 high energy laser. The analysis of 3D high speed recordings reveals lateral force components as well as angular momentum re-orientating the lightcraft towards the laser beam in the case of slight misalignment. Beam-riding properties are examined with respect to the initial lateral offset at the launch position. The results are compared with model data derived from raytracing analysis of the intensity distribution on the surface of an ignition pin which is located on the lightcraft’s symmetry axis. Based on model data, beam-riding abilities are characterized with respect to initial offset and inclination by means of Julia sets. The parameter space of tolerable misalignment is explored with respect to laser burst parameters and compared with experimental data.