Experiments on Indirect-driven Double-shell implosion at the ShenGuang-III laser facility with 100kJ laser energy

The double-shell implosion is a favorable candidate for the ignition by ICF.  The double-shell implosion experiments have been carried out on OMEGA with 15kJ laser energy and the highest DD neutron yield is 10⁸. Recent years, double-shell implosion work were carried out on NIF with 1MJ laser energy.

In our work, double-shell implosion with 6 shots have been performed on ShenGuang-III laser facility with 96kJ and 48 laser beams.Two type capsules(undoped ablator and doped ablator) were used to study the influence of M-band preheat and Pusher-Gas mix on double-shell implosion.  In our experiments,  the highest DD neutron yield of 9.1×10⁹ and 27% YOC_1D are obtained by undoped ablator shot.Simultaneously,1.5×10⁷ secondary DD neutrons are produced and 14mg/cm² fuel area density(~80% of 1D simulated) is inferred. On the other hand, the doped ablator shot get a lower neutron yield and YOC_1D is less than 10%. Furthermore, fall-line method was used to analysis two type implosions. And we proposed that the measured neutron yield is very close to “clean” neutron from Fall-line. The doped ablator implosion had a lower YOC_1D was comes from Pusher-gas mix. In sum, the fall-line analysis is very useful and the pusher-gas mix is very important in double-shell implosion.