Understanding the magneto-Rayleigh-Taylor instability (MRTI) in thin-shell implosions is critically important for Z-pinch dynamic hohlraum driven inertial confinement fusion. A nonlinear Rayleigh–Taylor instability (RTI) model has been developed for the implosion of a finite-thickness fluid shell in cylindrical geometry. Using this model, the effects of geometric convergence and finite shell thickness on single-mode RTI growth are systematically investigated. The results show that the contribution of these effects to perturbation growth becomes dominant over classical RTI growth in the late stage of cylindrical thin-shell implosion. Furthermore, both numerical simulations and theoretical analysis reveal that, under a constant implosion velocity of the Z-pinch plasma, the pre-stagnation perturbation amplitude of multi-mode structures increases linearly with the current rise time. To validate this scaling, three types of wire-array experiments featuring similar implosion dynamics and constant implosion velocities were performed on an 8 MA pulsed power generator. The experimental results—including X-ray radiation profiles and time-resolved X-ray images of the imploding plasma—along with corresponding numerical analysis, consistently demonstrate that pre-stagnation MRTI growth scales linearly with the current rise time, in excellent agreement with the theoretical prediction.

magneto-Rayleigh-Taylor,thin-shell implosion,Fast Z-pinch