On the benefits of using shorter rise-time current pulses to drive MagLIF implosions*

Magnetized Liner Inertial Fusion (MagLIF) is a Z-pinch magneto-inertial-fusion (MIF) concept studied on the Z Pulsed Power Facility at Sandia National Laboratories.  Two important metrics characterizing current delivery to a Z-pinch load are the peak current and the current-rise time, which is roughly the time interval to reach peak current.  It is generally known that MagLIF implosions benefit from shorter current-rise times [1].  A theory was recently developed based on similarity scaling [2] to understand this effect more precisely.  Using this framework, we analytically investigate the dependency on the performance of MagLIF loads when varying the current-rise time, or equivalently, the implosion timescale.  We compare predictions of the theory to 2D numerical simulations using the radiation, magneto-hydrodynamic code HYDRA.  Our findings suggest that MagLIF implosions driven by shorter current pulses are beneficial for (1) reducing the electro-thermal instability (ETI) and Rayleigh-Taylor instability (RTI) development, (2) increasing the implosion velocity and in-flight ram pressure of the liner, (3) improving the quality of the stagnation event across several metrics, and (4) reducing the electrical-energy requirements needed to drive the implosions.   At the end of this talk, we comment on how shorter current-rise times can be achieved on the Z machine, including a reconfiguration of the machine hardware that has been tested before and a current-switch mechanism based on exploding wire arrays [3].

[1] S. A. Slutz, Phys. Plasmas 25, 082707 (2018).

[2] D. E. Ruiz et al., Phys. Plasmas 30, 032709 (2023).

[3] G. C. Burdiak, Phys. Plasmas 22, 112710 (2015).