  Heating a solid with laser-accelerated fast electrons is unique way for a
laboratory experiment to generate a plane powerful shock wave with a pressure
of several hundred or even thousands of Mbar. Behind the front of such a
powerful shock wave, dense plasma is heated to a temperature of several keV.
Then, a high rate of radiation energy loss occurs even in low-$Z$ plasmas. The
effect of strong compression of matter due to radiation cooling in a gigabar
shock wave driven by fast electrons is found in computational and theoretical
researches. It is shown that the effect of radiation cooling leads to the
compression of matter in the peripheral region of shock wave to a density
several times larger than the density at its front. Heating a solid by a
petawatt flux of laser-accelerated fast electrons allows one to surpass the
gigabar pressure level of a plane shock wave, which is the maximum level for
the impact of laser-accelerated pellets. Higher pressure about 100 Gbar can be
achieved under laboratory conditions only when a spherical target is imploded
under the action of a terawatt laser pulse.
