  An exact turbulence universal scaling law-8/3 for the density fluctuations of
cosmic ray (CR) is obtained on the basis of a new analytical compressible
turbulence theory and known two-fluid model of the CR dynamics. It is shown
that the origin of this scaling law may be due to the breaking of the nonlinear
simple waves in CR medium near the scale of their Larmor radii as for the space
plasma of solar wind and magnetosheath.
