Current instability of “snow plough”

The hollow cylindrical liner collapsing to the axis as a result of compression by the magnetic field of the current passing though it is one of the basic schemes for the generation of bright X-pulse. The main factor deteriorating the efficiency of this scheme is widely believed to be an instability of the Reyleigh-Teylor type. The analysis of data obtained in the experiments with liners on the installations “Module-A5”, “Saturn” and “Angara-5)” [1, 2, 3] shows substantial discrepancy with the supposed Rayleigh-Taylor scenario of liner shell disruption. First of all this discrepancy can be seen in the fact that the stratification appears at the very beginning of acceleration phase, when liner is actually at its initial position. Besides, much attention must be paid to the fact that modulation scale along the axis increases with time, the rate of this process being to high for it to be explained by nonlinear dynamics of mass redistribution along the axis. All the above mentioned considerations lead us to the conclusion that in this case we deal with a current dynamics, which nevertheless — as can be seen in the experiments — could give rise to the fall-through of the current into the internal regions of the liner, thereby determining future behaviour of mass. In the experiments on the installation “Modul-A5” it was observed the exact correlation between the process of stratification and occurrence of the lighting kernal in the region near the axis (Fig.1 a,b).