Development of nonlinearity in a growing self-excited dust-density wave

The development of nonlinearity is observed in a naturally occurring planar dust-density wave. As it propagates through a dusty plasma, the wave grows and harmonics are generated. The amplitudes, wave numbers, and growth rates are measured for the fundamental and its harmonics. The energy in the harmonic modes exhibits a strong exponential increase with diminishing gas pressure, until it levels off at lower gas pressures. The wave numbers and growth rates for the harmonics are near integer multiples of those for the fundamental. (C) 2011 American Institute of Physics. [doi:10.1063/1.3544938]