Bispectral analysis of nonlinear compressional waves in a 2D dusty plasma crystal

Bispectral analysis was used to study the nonlinear interaction of compressional waves in a 2D strongly coupled dusty plasma. A monolayer of highly charged polymer microspheres was suspended in a plasma sheath. The microspheres interacted with a Yukawa potential and formed a triangular lattice. Two sinusoidal pump waves with different frequencies were excited in the lattice by pushing the particles with modulated Ar+ laser beams. Waves at the sum, difference, and other combination frequencies were shown to be the result of coherent nonlinear interaction of pump waves. However, for certain combination frequencies coherent nonlinear interaction was ruled out. PACS numbers: 52.27.Lw, 82.70.Dd, 52.35.Mw, 52.27.Gr [1] Electronic mail: [email protected]