Investigation of converging ultra-fast jets in cylindrical implosions: A new platform to study complex hydrodynamic effects relevant to inertial confinement fusion

We present the results of a computational study investigating an experimental platform that can furnish new insights on the stability of inertial confinement fusion (ICF) implosions. This novel design concept puts particular emphasis on the generation of very high Mach number jets, which are similar to flows observed in certain ICF target designs. The platform has been designed and modeled using FLASH, a highly versatile, parallel, adaptive mesh refinement, finite-volume Eulerian, radiation-magnetohydrodynamics code with extended physics capabilities. A directly driven, open-ended cylindrical ablator is manufactured with a series of carefully designed conical protrusions. These jet-generating features give a high degree of control over the characteristics on the inwardly propagating jet flows, their speed, collimation, etc., and the open geometry of the cylinder gives us a clear window to observe the flows over the entire implosion history. The behavior of this kind of converging flow, in the context of ICF, is still not well understood. This platform opens up the possibility of studying converging ultrafast jet propagation over a large parameter space, and it can be used to inform the design of ICF targets that may exhibit jetting phenomena.