Absorption Physics at 351 nm in Spherical Geometry

Absorption and energy partitioning have been measured for spherical targets irradiated on the OMEGA facility by six beams of nanosecond 351-nm laser radiation at intensities from ${10}^{13}$ to ${10}^{15}$ W ${\mathrm{cm}}^{-2\mathrm{}}$. Efficient collisional absorption is found, in agreement with one-dimensional simulations including refraction and inhibited transport, and very low levels (∼${10}^{-4\mathrm{}}$) of superthermal electron production are demonstrated.