  We for the first time observe that at the initial stage of a high-current
discharge, a low-divergence short (< 2 ns) electromagnetic pulse is formed over
a ferrite surface. The 50% part of this pulse lies in the region of fairly hard
x-ray radiation (photon energy >1 keV) with the energy $\approx$0.6 mJ and the
average power 0.3 MW. The radiation propagates parallel to the surface in the
anode direction with the angle divergence < 2$^{o}$. The high directionality of
the radiation in absence of the aperture-limiting devices for the radiation
beam and the quadratic dependence of the spatial radiation energy flux density
on the active part of the ferrite prism points to the coherent nature of the
observed radiation. A possible generation mechanism of the radiation is
proposed. It is based on the short-lived magnetization of the unit areas on the
ferrite surface by a high-power electromagnetic pulse and subsequent coherent
interference of the unit waves irradiated by these areas.
