Effect of a target size on the recoil momentum upon laser irradiation of absorbing materials

The dependence of a recoil momentum on the radius of a target irradiated by a single-pulse Nd³⁺:YAG laser (λ = 1.064 μm, τ = 20 ns, E≤300 mJ) in the air is studied. The recoil momentum decreases three-fold with increasing the relative target radius from 0.3 to 5 and tends to saturation for r>3. The calculation of the recoil momentum on the basis of the Euler and Navier–Stokes equations gave understated values for r>1, which lowered to negative values. The reasons for the qualitative discrepancy between the experimental and calculated data is discussed.