Measurements of Energetic X Rays from Laser-Produced Plasmas

The dependence of energetic x-ray emission from laser-produced plasmas on laser energy, pulse duration, and atomic number of the target ($Z=4\mathrm{} \mathrm{to} 42$) has been studied for irradiations of ${10}^{13}$ to ${10}^{16}$ W/${\mathrm{cm}}^2$. Energetic x-ray emission is more than ${10}^3$ times greater than bremsstrahlung expected for a Maxwellian electron velocity distribution and is more sensitive to energy density in the target than to power density.