Modeling of Linus-Type Stabilized Liner Implosions

Abstract

In this paper, the results of a number of theoretical studies associated with LINUS liner dynamics are presented. These studies include the effects of slight liner compressibility upon the basic state motion, the modeling of “open ended” liner systems required for plasma injection and compression and our latest approaches on one-dimensionally model the complicated liner flow fields including the effects of axial piston drive and the transition ducting connecting the annular piston with the cylindrical region of the liner.

ADINC, an implicit Langrangian hydrodynamics code is utilized to determine the onset of liner compressibility effects in terms of the system parameters. In particular we determine the induced asymmetry in the liner trajectory near the turning point as a result of the complicated internal compression wave structure migrating within the liner and interacting with the free surface and the solid drive-piston. Estimates of axial end losses in open ended sytems are made by means of a linearized wave analysis to calculate the time dependent induced axial velocity due to the acoustic accommodation of the incompressible pressure field to the open endwall holes. These axial velocities are integrated in time over the entire liner trajectory history to scale the lost liner material in terms of the system parameters. The basic state trajectory utilized above is determined, including the effects of axial piston drive and some of the details of the transmition ducting.