Here we report on the production of highly directed ion blocks by plasma interaction of ultraviolet wavelength light produced from a KrF laser. This may support the requirement to produce a fast ignition deuterium-tritium fusion at densities not much higher than the solid state by a single shot petawatt-picoseconds ultraviolet laser pulse. Using double Rayleigh initial density profiles, we are studying numerically how the nonlinear force necessary to accelerate plasma blocks may reach the highest possible thickness. Propagation of plasma blocks and the volumetric hot electrons can be shown in detail. Results of computations for wavelengths of two lasers are compared, which show that the block current density for a KrF laser is approximately four times bigger than for the Nd-glass lasers. This is in good agreement with the number predicted by theory.

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The analytical evaluation of the capability of Bremsstrahlung highly directional energetic g-beam to induce photo transmutation of 90 Sr (g,n) 89 Sr is presented. Photo transmutation of hazardous nuclear waste of 90 Sr, one of the two main sources of heat and radioactivity in spent fuel into valuable nuclear medicine radioisotope of 89 Sr is explained. Based on the calculations, a fairly decent fraction of gamma rays in this range are used in transmuting of 90 Sr into 89 Sr where according to the available experimental data it is shown that by irradiating a 1-cm thick 90 Sr sample with lasers of intensity of 10 21 W/cm 2 and repletion rate of 100 Hz for an hour, the reaction activity would be 1.45 kBq. It is shown that there is not a linear relationship between the growth of the activity and increasing the laser intensity, but there is a dramatic increase in the growth rate especially between 10 20 and 10 21 W/cm 2 . In this work, the advantage of photonuclear transmutation over the neutron capture transmutation for 90 Sr isotope is also discussed.