<p>A theoretical model of the experimentally observed collimation of soft radiation from a capillary discharge with hollow electrodes without the use of collimating optics has been proposed. The effect of focusing and channeling of hard radiation with a small difference of the refractive index of the discharge plasma from the vacuum value is possible with its multiple refractions on density disturbances caused by the generation of small-scale waves due to two-stream plasma instabilities. The numerical solution of the eikonal equation shows the possibility of such focusing in a periodic plasma structure. The conditions for focusing of hard radiation in a turbulent plasma structure for almost paraxial rays have been obtained by averaging the equations over an ensemble of stochastic wave disturbances, and the effect of focusing and channeling of the inner part of the beam, similar to that observed in a capillary discharge has been numerically demonstrated. The quasiperiodic structure of rays during channeling with alternating antinodes and nodes has been shown. Due to the fundamental nature of the processes under consideration, it can be expected that the phenomenon of focusing and channeling of X rays by density waves should be observed not only in capillary discharges, but also in jets from accretion disks around stars and black holes, which has been qualitatively demonstrated by comparing the numerical tracing results with astronomical observations by the Chandra X-ray Observatory.</p>