The 4th International Conference on Matter and Radiation at Extremes (ICMRE 2019)

394 / 2019-02-28 17:16:50

Experimental development of hydrodynamic instabilities on Shenguang laser facilities

Richtmyer-Meshkov instability; Rayleigh-Taylor instability; Reshock; Convergent geometry

Plenary track > Interface Instabilities at Extremes

Understanding and mitigation the hydrodynamic instabilities growth occuring during the implosion of an inertial confinement fusion (ICF) capsule is essential to achieving the desired fusion performance and ultimately achieving ignition with ICF. In an effort to better understand hydrodynamic instabilities in ICF implosion cores, a series of laser-driven hydrodynamic instability experiments have been conducted on Shenguang laser facilities.
The reshock experiment using planar target studies the physical process of deeply nonlinear regime and turbulence mix. The experiment uses laser to drive the two sides of shock tube to produce counter-propagating shocks, the interface evolves by action Richtmyer-Meshkov (RM) instability growth and its subsequent reshock, compression, and re-growth phases, and the growth is imaged with backlit x-ray radiography. The different perturbation shapes are used to study the difference of the growth with different initial perturbations.
Convergent geometry introduces effects not present in planar geometry such as shell thickening and growth caused purely by geometry due to the Bell-Plesset effect. Experiments have been done to investigate the effects of convergence on RM growth and Rayleigh-Taylor (RT) growth of decelerated regime. Side-on x-ray radiography is uesd to measure instability growth occurring between the inner surface of aluminium and plastic foam from well-characterized perturbation. The growth of decelerated regime RT growth is observed, as well as the feedout from the inner surface of aluminium to the outer surface of aluminium of the cylinder. Numerical simulations are in good agreement with the experimental results.