Proof-of-Principle Experiment on the Dynamic Shell Formation Concept on the OMEGA Laser

A dynamic shell implosion concept in direct-drive inertial confinement fusion utilizes

a spherical pellet of liquid DT, which is first compressed by convergent shocks,

then expands after bouncing these shocks from the center, decelerates and forms a shell

with the help of following subsequent converged shocks, and finally, implodes resulting

in conventional central hot-spot ignition [V. N. Goncharov et al., Phys. Rev. Lett. 125,

065001 (2020)]. Proof-of-principle experiments on the OMEGA laser were proposed to

demonstrate, for the first time, the feasibility of dynamic formation of a dense shell

in a spherically expanding cloud of plasma. This shell is formed by convergent shocks

launched at the edge of the cloud, with the cloud itself formed as a result of compression

and relaxation of a plastic-foam ball target. The results of experiments are expected

to be reported and compared with 2-D and 3-D radiation-hydrodynamic simulations.

These simulations predict good stability of the dynamic shells considered to low-mode

asymmetries induced by laser-illumination nonuniformities, target offset, and stalk mount.