  Radiation of relativistic charged particles in a system of randomly spaced
plates is considered in the paper. It is shown that for large number of plates
($N \gg 1$), in the wavelength range $\lambda \ll l\ll L$ (where $l$ is the
photon mean free path and $L$ is the system characteristic size) and for angles
$|\cos \theta |\gg (\lambda/2\pi l)^{1/3}$, pseudophoton diffusion represents
the major mechanism of radiation. Total intensity of radiation is investigated
and its strong dependence on the particle energy and plate number is obtained.
