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

Abstract

The 3D Richtmyer–Meshkov (RM) and Rayleigh–Taylor (RT) instabilities induced by a laser pulse of the Gaussian-like power profile on a metal surface in a ‘covered target configuration’ environment evolve into complex fluid dynamics with the new paradigm of wave-vortex phenomena in turbulent mixing. Such a RM instability (RMI)/RT instability (RTI) environment is generated in a semiconfined configuration (SCC) of the experiment which causes the extended vapor/plasma lifetime and fast multiple reshocks that strike the density interface. The Gaussian power profile causes different circular regions with a different momentum transfer, different Atwood number and different RMI/RTI morphology. In the central region (CR) of the Gaussian-like spot, where the momentum transfer and Atwood number are maximal, the oscillatory field of reshocks causes the separation of small and large bubbles, the 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 to larger bubbles in the process which can be represented by the ‘Lindenmayer tree’.

High-frequency periodic patterns driven by non-radiative fields coupled with Marangoni convection instabilities on laser-excited metal surfaces

“…In perspective, more advanced models should bring light on the surface dynamics driven by recoil pressure and by material redeposition from plasma plume at stronger ablation conditions and variety of insta-bilities, which can develop on nanosecond or even larger timescales at micro-and nanoscale, such as Rayleigh-Taylor, Rayleigh-Plateau and Kelvin-Helmholtz instabilities, instability driven by van der Waals forces etc. [18,20,33,36,37,50,[105][106][107][108][109][110].…”

Macroscopic and microscopic stabilization mechanisms of unstable interface with interfacial mass flux

“…1 Examples include thermonuclear flashes in type-Ia supernova, coronal mass ejections in the solar flares, downdrafts in planetary magnetoconvection, plasma instabilities in the Earth ionosphere, unstable laser ablated plasmas in inertial confinement fusion, and plasma thrusters. [2][3][4][5][6][7][8][9][10][11][12]30,35 While plasma processes are necessarily electro-magnetic with charged particles and magnetic fields, the better understanding of non-equilibrium dynamics of interfaces and mixing in neutral plasmas (fluids) is required for the grip and control of realistic plasmas at macroscopic (hydrodynamic) scales. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]35 This work investigates the interface dynamics with the interfacial mass flux and focuses on the interplay of the macroscopic and microscopic stabilization mechanisms with the destabilizing acceleration.…”

“…In plasmas, the interface is a boundary separating the phases of matter with distinct thermodynamics properties and having the interfacial mass flux, such as hot and cold plasmas in laser fusion. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The dynamics of interfaces with interfacial mass flux is a long-standing problem in science, mathematics, and engineering; it is challenging to study in theory, experiments, and simulations. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] To tackle these frontiers, the theory of interface dynamics was recently developed.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The dynamics of interfaces with interfacial mass flux is a long-standing problem in science, mathematics, and engineering; it is challenging to study in theory, experiments, and simulations. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] To tackle these frontiers, the theory of interface dynamics was recently developed. [17][18][19] It elaborated the general framework for the problem of interface stability, directly linked the microscopic interfacial transport to macroscopic flow fields, and identified the inertial mechanism of the interface stabilization and the new fluid instability.…”

“…16 These microscopic mechanisms may be present in realistic plasmas and may include radiation transport, dissipation, diffusion, and other effects. [3][4][5][6][7][8][9][10][11][12][20][21][22][23][24] Their influences on the interface dynamics call for systematic investigations. 1,17,30 The dynamics of neutral plasmas (ideal fluids) is governed at continuous scales by the laws of conservation of mass, momentum, and energy, with the closure equation of state.…”