Stability characteristics of Rayleigh-Taylor instability in a strongly coupled incompressible dust fluid with finite shear flow

The stability characteristics of Rayleigh-Taylor instability (RTI) has been investigated in an unmagnetized, strongly coupled dusty plasma in the presence of velocity shear. The description of the dust has been made through the Generalized Hydrodynamic model, where a strong correlation between the dust grains comes via the Maxwell relaxation time parameter. It has been found that when the correlations become stronger, the shear vortices that are originating from the RayleighTaylor (RT) dynamics tend to propagate through the medium, giving a lesser opportunity to the RT mode to grow. Physically, in the strongly coupled regime, viscosity contributes to the dispersive correction, instead of normal dissipation in the RT mode and reduces the gravitational energy which is the main factor responsible for the RTI. In this process, shear flow also helps to stabilize the RT mode by extracting energy from the gravitational energy. Due to this combined effect, the long wavelength modes grow first and the shorter ones get completely suppressed. The results, first, have been obtained by local approximation and thereafter via nonlocal analysis with numerical techniques. A cut-off value of the wave vector, for the RT mode, has also been obtained analytically, which closely matches with the numerical one in the shorter wavelength regime. Published by AIP Publishing.