A 6 MJ spherical hohlraum target for heavy ion inertial fusion

A new target option for energy applications of heavy ion inertial fusion is analysed. It has a spherical hohlraum and is irradiated by ion beams along the directions of the zeros of the fourth Legendre polynomial P-4. The tar get performance is simulated with a 1-D three temperature hydrodynamics cod e and with a 2-D view factor code. Its efficiency is shown to depend crucia lly on the structure of the hohlraum wall, which, simultaneously, plays the role of the X ray converter. For an optimized pulse power profile, a 1-D e nergy gain of G = 78 is calculated with an input energy of E-dr = 6.1 MJ in the form of 5 GeV Bi-209 ions focused on the target sphere with an outer r adius of R = 6.37 mm.