Experimental study of fill-tube hydrodynamic effects on implosions using capsules with plastic stalks

Cryogenic ignition experiments at the National Ignition Facility (NIF) are expected to use a fill tube to introduce liquid DT into the capsule prior to solid layer formation. This fill tube is expected to form a hydrodynamic jet during the deceleration phase of the implosion. Numerical simulations indicate that a 10$\mu $m tube with a 3$\mu $m hole has an acceptable impact on implosion performance, but experimental data validating these simulations are lacking. We therefore initiated experiments at the Omega laser facility to explore the hydrodynamic effects of stalks on implosion performance, and we recently obtained high-quality x-ray images of hydrodynamic jets created by 9-37 $\mu $m diameter stalks made of PAMS (polyalpha-methylstyrene). We discuss the experiments and compare the results to simulations