Authors: Brandon K. Russell (University of Michigan), Paul T. Campbell (University of Michigan), Chuanfei Dong (PPPL), Karl Krushelnick (University of Michigan), Alexander G. R. Thomas (University of Michigan), Philip M. Nilson (LLE, University of Rochester), Gennady Fiksel (University of Michigan), Louise Willingale (University of Michigan)

Laboratory studies of microphysics (e.g., shock formation, reconnection) can provide insight into phenomena observed in astrophysical systems. Lasers are a particularly useful tool for generating the high-energy conditions necessary to drive shocks or to generate strong magnetization for reconnection studies. In our work on the Omega EP laser system we studied a highly asymmetric interaction formed by focusing a long pulse laser to ~10¹⁴ W/cm²  at a small separation from a relativistic intensity >10¹⁹ W/cm² short pulse laser on a thin CH foil. Proton radiographs taken normal to the surface of the target show a modification of the quasi-static magnetic fields of the long-pulse generated plasma plume at the interaction point between the two plumes. Forward modeling shows that this modification is evidence for magnetized shock formation. A 3D OSIRIS particle-in-cell simulation of the interaction shows that the self-generated magnetic fields of the short-pulse plasma drape around the long-pulse plasma, forming an unstable contact discontinuity from which a shock is driven. Electron particle tracks show the possibility of shock drift acceleration (SDA) in the interaction.