Influence of Capsule Offset on Radiation Asymmetry in Shenguang-II Laser Facility^*

The re-emitted images of the frame camera indicated that the high-Z (Bi) capsule deviated about 29 μm from the center of the hohlraum in experiments at the Shenguang-II (SG-II) laser facility; however, investigations on this issue have seldom been performed. The influence of three dimensional offsets of a capsule on its radiation asymmetry in inertial confinement fusion (ICF) will be analyzed in this paper. Simulations demonstrate that the axial offset of 100 μm of a capsule from the center of the hohlraum brings an additional 3.5% radiation drive asymmetry and 6.5% P₁ asymmetry (Legendre odd model) on the capsule in the SG-II laser facility, and the offset must be within 25 μm if the P₁ asymmetry is restricted to below 2%.