Suppression of a spontaneous dust density wave by modulation of ion streaming

Synchronization of a self-excited dust density wave has been experimentally investigated in a strongly coupled dusty plasma. A dust density wave of frequency ∼78 Hz is spontaneously generated from the dust void boundary due to the ion streaming instability. The electric field in the dust void region is measured, and the electric field force and ion drag force on the dust particles at the void boundary are estimated to explain the mechanism of spontaneous dust density wave excitation. Synchronization occurring through the suppression mechanism is observed by modulating the ion streaming by applying an external sinusoidal signal to the dust void. At sufficiently high modulation amplitude, the onset of period-doubling bifurcation is observed. Fast Fourier transform spectral analysis is done using time-series data obtained from high-speed video imaging. The van der Pol equation with a force term is used to correlate the observed suppression phenomena.