<u>Systematic measurements of quasi-static B-fields from laser-driven coil targets in intensity regime relevant for magneto-inertial fusion experiments</u>

Strong quasi-static magnetic fields to be applied in high-energy density plasma experiments can be driven from laser interactions with coil-targets (CT), which geometry provides easy access for several diagnostics and do not produce a significant quantity of debris.

We demonstrated the generation of quasi-static magnetic fields of tens of Teslas using a 500 J, ns laser, focused to ~10¹⁵ W/cm². The B-field was characterized using proton deflectometry at two perpendicular probing axes. Data confrontation with particle test simulations reveal features that can be distinctively linked to the looping current and with static charging of the wire surface.  Discharge currents of ˜25 kA (yielding ˜60 T at the center of 500 µm-diameter coils) are fully consistent with our predictions based on the plasma diode model, which has been continuously improved and validated through benchmarking experiments over the past years. The studied intensity regime is of interest for ns laser-drive available at large scale laser facilities such as Omega, NIF, or LMJ, where it is possible to carry out magneto-inertial-fusion experiments.

 

*Work supported by the NNSA/NLUF Grant DE-NA0003940, Grant No. PID2019-108764RB-I00 (MICINN,

Spain) and EUROfusion Consortium under grant agreement No. 633053.