Inertial confinement fusion with tetrahedral hohlraums at OMEGA

Indirect-drive inertial confinement fusion will require for ignition a high ly symmetric x-ray flux around the capsule. To this end, the "tetrahedral h ohlraum," spherical in shape with four laser entrance holes located at the vertices of a tetrahedron, has been proposed. The first experimental test o f this concept, using the OMEGA laser, is reported here. Drive symmetry was probed using capsule implosion symmetries, which varied qualitatively as e xpected with hohlraum dimensions. Modeling of the experiments gives time-av eraged flux asymmetries as low as 1% rms over a 2.2-ns laser pulse.