engleski

Laser-generated Richtmyer–Meshkov and Rayleigh–Taylor instabilities in a semiconfined configuration: bubble dynamics in the central region of the Gaussian spot

The 3D Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities induced by the laser pulse of Gaussian-like power profile on metal surface in the environment of the “covered target configuration” evolve into complex fluid dynamics with the new paradigm of wave-vortex phenomena in turbulent mixing. Such RMI/RTI environment is generated in the semiconfined configuration (SCC) of experiment which causes the extended vapor/plasma lifetime and fast multiple reshocks that strike density interface. Gaussian power profile causes different circular regions with different momentum transfer, different Atwood number and different RMI/RTI morphology. In the central region of Gaussian-like spot, where the momentum transfer and Atwood number are maximal, the oscillatory field of reshocks causes separation of small and large bubbles, growth of bubble penetration depth and of bubble size by the formation of bubble pairs inside the cluster and their merging. Discrete merging jumps give rise of larger bubbles in the process which can be represented by the «Lyndenmayer tree».

Laser ablation ; Richtmyer-Meshkov instability ; Rayleigh-Taylor instability ; fast reshocks ; bubble separation by size ; bubble merging ; bubble flattening ; Lindenmayer tree

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