Fusion Science and Technology / Volume 51 / Number 4 / May 2007 / Pages 753-757
The fuel layering process of a cryogenic target for the Fast Ignition Realization EXperiment (FIREX) project has been studied. A foam shell method is proposed as a fuel layering technique for this target design. The difficulty of the fuel layering comes from the aspherical target symmetry. In the case of the foam shell method, liquid fuel is directly infiltrated into a foam shell though a fuel feeder and is soaked up into the foam layer by capillarity. The fuel is then solidified and an ideal cryogenic target is formed. To date, the cryogenic system for the demonstration of the fuel layering was fabricated and subsequently modified to improve its cool-down performance. A dummy foam target has been utilized to study the fuel layering process using H2 instead of D2 and DT fuels. Liquid H2 is supplied into the shell through a feeder with a 20 m inner tip diameter. The solid H2 quantity remaining in the shell was controlled by regulating both H2 pressure and target temperature during solidification.