Analysis of the Liner Stability in Various Experiments

The main problem occurring at cylindrical liner acceleration by azimuthal magnetic field is its motion distortion caused by the combination of the Rayleigh-Taylor (RT) and the sausage instabilities, which, in principle, can lead to complete liner destruction. The strength of the material can inhibit the development of such instabilities; however, as far as melted liner section thickness increases due to ohmic heat, the instabilities start to develop fast. The experiments have shown, that even similar acceleration conditions may result in significantly different states of liners with different degrees of their distortion. Thus, in similar conditions of the LD, HF and NTLX experiments, the X-ray images for the HF and NTLX experiments showed liners' homogeneity, suggesting that their motion was comparatively stable, while the X-ray images made for the LD experiments showed that the liners external surfaces were seriously distorted due to the perturbations growth. In this work 2D MHD computations are presented for liner LD, HF and NTLX implosions with consideration of perturbation growth. Initial perturbations were considered as random with characteristic values determined by the resolution of used computational grid. Computation results have shown, that, in fact, the conditions of the HF and NTLX experiments lead to smaller perturbation growth, than those of the LD experiments, if the value of perturbation growth is determined over the perturbation development on the internal surface.