  In a dusty plasma, an impulsively generated shock, i.e., blast wave, was
observed to decay less than would be expected due to gas friction alone. In the
experiment, a single layer of microparticles was levitated in a radio-frequency
glow-discharge plasma. In this layer, the microparticles were self-organized as
a 2D solid-like strongly coupled plasma, which was perturbed by the piston-like
mechanical movement of a wire. To excite a blast wave, the wire's motion was
abruptly stopped, so that the input of mechanical energy ceased at a known
time. It was seen that, as it propagated across the layer, the blast wave's
amplitude persisted with little decay. This result extends similar findings, in
previous experiments with 3D microparticle clouds, to the case of 2D clouds. In
our cloud, out-of-plane displacements were observed, lending support to the
possibility that an instability, driven by wakes in the ion flow, provides
energy that sustains the blast wave's amplitude, despite the presence of gas
damping.
