Shock Melting of a Two-Dimensional Complex (Dusty) Plasma

Shock waves with a linear front were experimentally studied in a monolayer hexagonal Yukawa lattice which was formed from charged monodisperse plastic microspheres and levitated in the sheath of a radio-frequency discharge. It was found that the shock can cause phase transitions from a crystalline to gaslike and liquidlike states. Melting occurred in two stages. First, the lattice was compressed in the direction of shock propagation and second, the particle velocities were randomized a few lattice lines downstream. The Mach number of the shock reached 2.7.