High flux symmetry of the Spherical Hohlraum with Octahedral 6LEHs at a Golden Hohlraum-to-capsule Radius ratio

Abstract: In the present Letter, we investigate a spherical hohlraums with octahedral six laser entrance holes (LEHs) for inertial fusion, which has advantages over the conventional hohlraums of cylindrical geometry since it contains only one cone at each LEH and the problems caused by the beam overlap and crossed-beam energy transfer can be eliminated and the backscattering can be reduced. In particular, our study indicates that at a specific hohlraum-to-capsule radius ratio, i.e., the golden ratio, the flux asymmetry on capsule can be significantly reduced. From our study, this golden octahedral hohlraum has robust high symmetry, low plasma filling and low backscattering. Though the golden octahedral hohlraum needs $30\%$ more laser energy than traditional cylinder for producing the ignition radiation pulse of 300 eV, it is worth for a robust high symmetry and low backscattering. The proposed octahedral hohlraum is also flexible and can be applicable to diverse inertial fusion drive approaches. As an application, we design an ignition octahedral hohlraum for the hybrid drive.