  The measurement of the propulsion of metallic microdroplets exposed to
nanosecond laser pulses provides an elegant method for probing the ablation
pressure in dense laser-produced plasma. We present the measurements of the
propulsion velocity over three decades in the driving Nd:YAG laser pulse
energy, and observe a near-perfect power law dependence. Simulations performed
with the RALEF-2D radiation-hydrodynamic code are shown to be in good agreement
with the power law above a specific threshold energy. The simulations highlight
the importance of radiative losses which significantly modify the power of the
pressure scaling. Having found a good agreement between the experiment and the
simulations, we investigate the analytic origins of the obtained power law and
conclude that none of the available analytic theories is directly applicable
for explaining our power exponent.
