Since the photons transfer momentum much more efficiently to electrons through Thomson scattering, selective acceleration of electrons will take place in an anisotropic radiation field, thus contributing to an electric current generation. The authors consider an optically thick, fully ionized, hydrogen plasma with the temperature gradient (dT/dZ) and the velocity shear (dVx/dZ) in a slab geometry (no spatial dependence in x- and y-directions). They calculate the current generation rate in the direction of the plasma flow velocity (x-direction) as the function of dT/dZ and dVx/dZ.