Coherent excitations in dust acoustic wave turbulence

Po-Cheng Lin¹, Ya-Yi Tsai¹, Mei-Chu Chang¹, Lin I^1*

¹Department of Physics, National Central University, Jhongli, Taiwan

* Presenter:Lin I, email:lini@phy.ncu.edu.tw

Unlike intuitive expectation, turbulence exhibiting a continuous power spectrum is not completely disordered. Multi-scale vortices winding around their worm-like vortex core filaments are good examples of coherent excitations in hydrodynamic turbulence. Nevertheless, the demonstration and the spatiotemporal behaviors of multiscale spatiotemporal coherent excitations in wave turbulence are still open issues, especially for three dimensional acoustic type traveling waves. The dust acoustic wave (DAW), spontaneously excited in the dusty plasma system with micro-meter sized dust particles negatively charged and suspended in the low pressure gaseous discharge, is a good platform for addressing the above issues through direct monitoring dust density fluctuations over a large area. In this talk, our past works on the above issues in the 3D traveling dust acoustic wave turbulence are briefly reviewed. The spontaneous excitations of acoustic vortex pairs winding around low amplitude filament pairs with conjugate topological charges in the weakly disordered DAW, excitations of multiscale acoustic vortices and their mutual coupling through decomposing DAW turbulence into multiscale coherent wave modes, the excitation of extremely large amplitude events, rogue waves, etc., will be presented and discussed.

Keywords: dust acoustic wave , wave turbulence , rouge wave , acoustic vortex