Simulations of the MARZ (Magnetically Ablated Reconnection on Z) platform

In extreme astrophysical environments, such as black hole coronae and pulsars, magnetic reconnection proceeds alongside strong radiative cooling, which modifies the energy partition and pressure balance within the reconnection layer, and may trigger cooling instabilities. Through the Z Fundamental Science Program (ZFSP), the MARZ (Magnetically Ablated Reconnection on Z) collaboration was awarded four shots on Z in FY22-23 in order to study radiatively cooled magnetic reconnection driven by the Z Machine at Sandia National Laboratories*, the world’s largest pulsed-power facility.

In this talk, we present 2D and 3D resistive MHD simulations of the MARZ platform using the GORGON code, using either a recombination radiative loss model, or a more complex model based on tabulated emissivities and opacities. The simulations predict the formation of a hot, dense layer with super-Alfvénic outflows. Plasmoids form within the layer due to the tearing instability, the current primarily flows through the plasmoids, resulting in localized heating. As the layer density increases, the layer undergoes a rapid radiative collapse due to the removal of the layer thermal pressure by radiative cooling. These simulations were used to design the MARZ platform and were post processed using the XP2 code to create synthetic diagnostics which were used to inform the experimental design.