Magnetized ICF implosions: ignition at low laser energy using designs with more ablator mass remaining

Abstract

This paper is the first work to redesign a spherical ICF implosion to best utilize the benefits of applying an external magnetic field. The sub-ignition experiment N170601 is taken as the baseline design, which used 1.57MJ of laser energy. The optimum magnetized design benefits from increasing the shell thickness by 14$\mu$m and decreasing the ice thickness by 18$\mu$m, resulting in a neutron yield of 8.9$\times$10$^{17}$. This is 34$\times$ greater than the unmagnetized simulation of the same design, and 18.5$\times$ the greatest unmagnetized simulation across all designs simulated. The resultant implosion velocity for the magnetized design is lower, which would also reduce ablation front instability growth. This design was found by using a simplified 1D magnetization model, then validated against full 2D extended-MHD capsule simulations with radiation asymmetries applied to correct the shape.