Modeling the First Magnetized NIF Hohlraum Implosions

We have performed 7 room-temperature hohlraum-driven implosions on NIF, with imposed magnetic fields in the capsule of 0 - 26 Tesla (J. D. Moody et al., submitted to Phys. Rev. Lett.). We have modeled these shots with the radiation-magneto-hydrodynamic code Lasnex, and developed multipliers on the laser power and cone fraction (inner / total beam power) to match observed time of peak capsule emission and hotspot x-ray shape. The values are similar to those needed for comparable BigFoot shots (C. A. Thomas et al., Phys. Plasmas 2020), and do not clearly vary with imposed field. Cross-beam energy transfer (CBET) removes the need for cone fraction multipliers, though with a lower δn_e/n_e saturation clamp (5*10^-4 – 2*10^-3) than typical for current NIF platforms (~0.01). Fusion yield and ion temperature agree well with BigFoot data but less well for our platform - with or without imposed field - in an absolute sense (yields 2-6x data). The modeling is close to the measured relative effect of a 26 T field: 1 keV Tion increase, 2.7x yield increase. We are using capsule-only modeling to quantify different sources of discrepancy, such as capsule quality, longer coast time, lower capsule gas fill density, and capsule fill tube perturbation.