  In a novel experiment that images the momentum distribution of individual,
isolated 100-nm-scale plasmas, we make the first experimental observation of
shock waves in nanoplasmas. We demonstrate that the introduction of a heating
pulse prior to the main laser pulse increases the intensity of the shock wave,
producing a strong burst of quasi-monochromatic ions with an energy spread of
less than 15%. Numerical hydrodynamic calculations confirm the appearance of
accelerating shock waves, and provide a mechanism for the generation and
control of these shock waves. This observation of distinct shock waves in dense
plasmas enables the control, study, and exploitation of nanoscale shock
phenomena with tabletop-scale lasers.
