The emergence of inertial waves from coherent vortex source in strongly coupled dusty plasma

Abstract

The evolution of isotropic, nondispersive, inertial waves emerging from an unsteady initial coherent vortex source is studied for strongly correlated dusty plasma using two-dimensional molecular dynamics simulation. In this study, the effects of azimuthal speed of a vortex source, strong correlation, large screening, and the compressibility of the medium on the propagation of generated inertial waves have been presented. It has been observed that these inertial waves only exist when the angular speed or azimuthal speed of the vortex source (U0) is larger than the transverse sound speed (Ct) of the system. The estimated speed of the nonlinear wave (CNLW) is found to be always larger and close to longitudinal sound speed (Cl) of the system for the range of coupling and screening parameters studied. We find that spontaneously generated inertial wave speed in dusty plasma is suppressed by the compressibility and dust-neutral drag of the system and is less sensitive to coupling strength. We also report a transition from “incompressible to compressible” flow. This transition is found to depend on the screening parameter and azimuthal speed of the vortex source. The existence of a critical Mach number Mc≈0.35 is found (where Mc=U0/Cl), above which inertial waves are found to exist, indicating the compressible nature of the wave.