INVESTIGATING THE EFFECT OF EXTERNAL MAGNETIC FIELDS ON HIGH-YIELD ICF DESIGNS

It has been demonstrated in simulation [1-4] and experiment [5] that applied magnetic fields can enhance performance, particularly when the implosion is not robustly burning [6,7]. The primary mechanism for this is magnetic insulation, whereby magnetic fields constrain electron heat flow out of the hotspot perpendicular to magnetic field lines as well as reduce the effective alpha stopping length as they transition to gyro-orbits. As the baseline, unmagnetized performance increases, the hotspot ion temperature becomes substantively hot enough that further temperature enhancement via magnetization does not contribute as significantly to increased DT nuclear reactions while magnetically induced asymmetries remain. As we magnetize increasingly performant shots, from N210808 (1.3 MJ yield) [8] to N221204 (3.2 MJ yield) [9] to a future Enhanced Yield Capability design (30 MJ yield) [10], all HYBRID-E-based designs and all using high density carbon ablators, magnetically enhanced performance saturates and flatlines. As NIF’s successes further advance, work has been begun on designing a Next Generation facility using a 10 MJ laser drive. It is envisaged that 100’s of MJs of yield could be achieved with such a facility. This begs the question whether magnetization can still benefit such a facility when implosions so robustly burn at high temperatures (𝑇𝑇𝑖𝑖~50 keV). Preliminary work here is presented on the effect of magnetization on initial Next Generation designs and how it affects their performance using LASNEX simulations.

References

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[4] Djordjević, B. Z., et al., 2025, POP, in preparation

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[8] Abu-Shawareb, H., et al., 2022, PRL 129, 075001

[9] Abu-Shawareb, H., et al., 2024, PRL 132, 065102

[10] MacLaren, S. A., et al., 2024, HEDS. 52, 101134