Radiation driven targets for heavy ion fusion

The baseline hohlraum configuration for heavy ion fusion has the radiation converters placed at opposite ends. For a capsule that absorbs about 1 MJ and has an initial radius of 0.234 cm, the minimum initial capsule to hohlraum surface area ratio that can provide an adequate time dependent symmetry requirement for a capsule implosion is about 0.075, based on calculations using the view factor code GERTIE. The capsule implosion is calculated by using the hydrodynamic code HYADES. The energy coupling efficiency between the hohlraum and the capsules is 21%, the peak hohlraum temperature is 260 eV, and the gain of this target system can be as high as 80. By placing the converters outside the hohlraum, the radii of the converters can be varied according to the beam focusing requirements while the hohlraum dimensions remain unchanged. By bending the radiation converters by 90 deg., a hohlraum configuration can be obtained that requires the ion beams to come in from only one direction. (author). 5 refs, 8 figs