Abstract

The abundance of solar energy outside the Earth makes attractive the electricity production in space. Initial proposals have been based on the energy transportation by microwaves. However, recent progress in laser science has stimulated research into the feasibility of using laser-based orbit systems in which laser radiation is utilyzed for transport of converted solar energy to the ground [1, 2]. Note that for even for diffraction limited beams one must have precision focusing optics in the space and a large ground-based receiver to facilitate efficient power transport and collection. Here we propose to exploit a self-focusing effect in the atmosphere to assist delivering powerful laser beams. Usually, for beams with power exceeding the critical power for self -focusing, uncontrolled beam filamentation and beam break up takes place. In this work we demonstrate that when the self-focusing length is comparable with the atmosphere height, the catastrophic self-focusing can be greatly suppressed and a smooth compression of the whole beam is possible. To illustrate the idea, without loss of generality we consider a laser beam propagating vertically through the earth's atmosphere from space to ground.

© 2009 IEEE