TRANSITION TO TURBULENCE IN PLASMA JET EXPERIMENTS

摘要

The transition from unsteady flow to turbulence is a long-standing issue, common to both astrophysics and laboratory high energy density plasma physics. A platform has been developed to address this issue via the evolution of a supersonic jet on the OMEGA laser. The experiment is based on a highly successful series of indirectly driven experiments fielded on both NOVA and OMEGA. Supersonic jet formation, evolution and interaction with a counter-propagating shock front have been studied. This platform has been modified to direct-drive to allow the very late-time behaviour to be observed. The Kelvin-Helmholtz instability is used to provide an initial seed from which the turbulence can develop. Numerical and analytical methods are employed to assess the requirements for a regime to make the transition to turbulent flow. Details of the experiment will be presented, and a variety of simulations in 2D and 3D calculations used to illustrate its evolution.