Entangling Defect Filaments in Dust Acoustic Wave Turbulence
Po-Cheng Lin1*, Lin I1
1Department of Physics, National Central University, Jhongli, Taiwan
* Presenter:Po-Cheng Lin, email:lkk12342001@gmail.com
Wave turbulence, with a continuous spectrum of multi-scale interacting waves, often occurs in many nonlinear wave systems, such as water, optical, acoustic and plasma waves. Past studies mainly focused on the scaling of power spectra, non-Gaussian dynamics and wave mixing, but less extent on the spatiotemporal waveform dynamics. Dust acoustic wave, a longitudinal wave composed of oscillating negatively charged micrometer-sized dust particles self-excited in plasma by ion streaming, is a good platform for large area direct waveform tracking because of its proper spatiotemporal scales. In this work, using dust acoustic wave turbulence as a platform, we experimentally demonstrate that, through multi-dimensional empirical mode decomposition, the dust acoustic wave turbulence can be view as a zoo of interacting multiscale acoustic vortex excitations with helical waveforms winding around defect filaments, akin to multiscale vortex excitations in hydrodynamic turbulence. How to decompose turbulent waveforms and the interactions between multiscale coherent acoustic vortices will be discussed.

Keywords: Dust acoustic wave, Multiscale, Acoustic vortex