engleski

Laser–matter interactions : Inhomogeneous Richtmyer–Meshkov and Rayleigh–Taylor instabilities

In this experimental study the ablative Richtmyer-Meshkov (RM) and the Rayleigh-Taylor (RT) instabilities were generated by the laser pulse of Gaussian-like power profile. The initial multimodal perturbation, the inhomogeneous momentum transfer and different Atwood numbers generate different shapes of spikes and bubbles in the central region (CR) and the near-central region (NCR) of the spot. A one dimensional Gaussian-like power profile causes the formation of the wavy-like rows of aperiodic spikes. The periodic spike segments inside the rows appear due to locally coherent flow. In the NCR, the mushroom-shape spikes tend to the organization on the isotropic square and the anisotropic rhombic lattices. The increase of the lattice periods 2, 3 or 4 times indicates formation of superstructures. The growth of sharp asymmetric RM/RT spikes in the CR is fast, uncorrelated and linear, while the growth of the symmetric mushroom-shape ones in the NCR is slow, correlated and nonlinear.

Richtmyer-Meshkov instablity; Rayleigh-Taylor instability; Turbulent mixing; Self-similar structures; Coherent structures

Rad prezentira posve nove spoznaje o razvoju Richtmyer-Meshkov i Rayleigh-Taylor nestabilnostima i korigira neke do sada prihvacene spoznaje.