Abstract

The laser beat wave scheme is capable of creating a coherent large longitudinal electric field E_L ~ mcω_p/e of the order of 1 GeV/cm. Applying this scheme to an ultrahigh-energy accelerator has been considered. Three difficulties associated with the original schemes are (1) the longitudinal plasma mismatch between the plasma wave and the high-energy particles; (2) the tendency of laser light to spread in the transverse direction; (3) the electromagnetic pump wave depletion. We have proposed that a plasma fiber in the appropriate conditions possesses the ability to simultaneously overcome (1) and (2); namely, the plasma duct (fiber), in which two laser lights propagate and the plasma density is low inside and high outside, in certain conditions sustains a plasma beat wave phase velocity equal to any prescribed velocity including the speed of light. In addition, the plasma fiber confines the light over a long distance without transverse spreading.

© 1986 Optical Society of America