Institute For Plasma Research, A CI of Homi Bhabha National Institute, Bhat, Gandhinagar, Gujarat, 382428, India.
Physics Department, Auburn University, Auburn, AL, 36849, USA.
Sci Rep. 2023 Mar 9;13(1):3979. doi: 10.1038/s41598-023-30992-3.
We report the first experimental observations of a single-mode Kelvin-Helmholtz instability in a flowing dusty plasma in which the flow is compressible in nature. The experiments are performed in an inverted [Formula: see text]-shaped dusty plasma experimental device in a DC glow discharge Argon plasma environment. A gas pulse valve is installed in the experimental chamber to initiate directional motion to a particular dust layer. The shear generated at the interface of the moving and stationary layers leads to the excitation of the Kelvin-Helmholtz instability giving rise to a vortex structure at the interface. The growth rate of the instability is seen to decrease with an increase in the gas flow velocity in the valve and the concomitant increase in the compressibility of the dust flow. The shear velocity is further increased by making the stationary layer to flow in an opposite direction. The magnitude of the vorticity is seen to become stronger while the vortex becomes smaller with such an increase of the shear velocity. A molecular dynamics simulation provides good theoretical support to the experimental findings.
我们报告了在流动尘埃等离子体中首次观察到的单一模式 Kelvin-Helmholtz 不稳定性，其中流动本质上是可压缩的。实验是在反向 [Formula: see text] 形状的尘埃等离子体实验装置中在直流辉光放电氩等离子体环境中进行的。在实验室内安装了一个气体脉冲阀，以启动到特定尘埃层的定向运动。在运动层和静止层的界面处产生的剪切导致 Kelvin-Helmholtz 不稳定性的激发，从而在界面处产生涡结构。不稳定性的增长率随着阀中气体流速的增加和尘埃流的可压缩性的相应增加而降低。通过使静止层反向流动，可以进一步增加剪切速度。随着剪切速度的增加，涡度的大小变得更强，而涡变得更小。分子动力学模拟为实验结果提供了很好的理论支持。
