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Kelvin-Helmholtz instability in a compressible dust fluid flow

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SCIENTIFIC REPORTS
卷 13, 期 1, 页码 -

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NATURE PORTFOLIO
DOI: 10.1038/s41598-023-30992-3

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We present the first experimental observations of a single-mode Kelvin-Helmholtz instability in a flowing dusty plasma with compressible flow. The experiments were conducted in an inverted D-shaped dusty plasma experimental device in a DC glow discharge Argon plasma environment. By introducing directional motion to a specific dust layer, the shear between the moving and stationary layers excites the Kelvin-Helmholtz instability, resulting in a vortex structure at the interface. The growth rate of the instability decreases with increasing gas flow velocity and compressibility of the dust flow, and the shear velocity is further increased by flowing the stationary layer in the opposite direction. Molecular dynamics simulations support these experimental findings.
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 D-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.

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