By means of the developed two dimensional radiation magneto-hydrodynamic Lagrangian code MULTI2D-Z, the dynamic hohlraums, which are consisted of tungsten plasma shell and low density foam cylinder with or without an embedded hard foam layer on it and a capsule in its center, are simulated. We understand the effects of the hard foam layer on the hohlraum radiation field, and the coupling of capsule and hohlraum for the capsule fusion, by comparing the simulated results of different configuration hohlraums. After applying a hard foam layer on the low density foam cylinder, the time, uniformity, and the first peak value of radiation field, which was receipted by the capsule, was delayed, increased, and reduced, respectively. Furthermore, the radiation temperature on the capsule surface is smoothly increasing, and the dwelling time of the hohlraum is prolonged. By optimizing the position and mass density of the hard foam layer and the capsule size, the time variation of the radiation temperature becomes close to that measured in National Ignition Facility (NIF) hohlraum in which a capsule was imploded and fusion energy of 1.37MJ was released. After embedding a capsule into the center of low density foam cylinder, the radiation temperature receipted by the capsule increases. That implies that both the hard foam layer and the coupling of a capsule and Z-pinch dynamic hohlraum are good for the capsule ablating implosion.

 

Z-pinch dynamic hohlraum, Radiation field modulation, Inertial confinement fusion (ICF), Capsule