MODAL AND FOCUSING PROPERTIES OF PLASMA BASED WAVE-GUIDES FOR X-RAY-BEAMS

Modal and focusing properties of the plasma based waveguide having a p arabolic profile of the electron density are treated for x-ray beams w ith the ray-transfer and paraxial-envelope equations. Conditions on th e single mode, multimode and leaky mode propagation in straight and ta pered plasma channels are evaluated. The near- and far-field patterns of these modes are calculated. The main result is that the mode struct ure is guide length and wavelength dependent, resulting in the guide l ength and wavelength dependent conditions for the guiding and focusing . The modal analysis finds its application in the field of x-ray laser s, extremly high harmonic generation and x-ray beam focusing, in which it may be helpful to design guides for optimum beam propagation. Futh ermore, the mode properties are extremly simple and provide an idealis ed model for the real plasma waveguides.