DOI: 10.7910/dvn/x3pb10
title: Experimental observations of detached bow shock formation in the interaction of a laser-produced plasma with a magnetized obstacle

description: The magnetic field produced by planets with active dynamos, like the Earth, can exert sufficient pressure to oppose supersonic stellar wind plasmas, leading to the formation of a standing bow shock upstream of the magnetopause, or pressure-balance surface. Scaled laboratory experiments studying the interaction of an inflowing solar wind analog with a strong, external magnetic field are a promising new way to study magnetospheric physics and to complement existing models, although reaching regimes favorable for magnetized shock formation is experimentally challenging. This paper presents experimental evidence of the formation of a magnetized bow shock in the interaction of a supersonic, super-Alfvenic plasma with a strongly magnetized obstacle at the OMEGA laser facility. The solar wind analog is generated by the collision and subsequent expansion of two counter- propagating, laser-driven plasma plumes. The magnetized obstacle is a thin wire, driven with strong electrical currents. Hydrodynamic simulations using the FLASH code predict that the colliding plasma source meets the criteria for bow shock formation. Spatially resolved, optical Thomson scat- tering measures the electron number density, and optical emission lines provide a measurement of the plasma temperature, from which we infer the presence of a fast magnetosonic shock far upstream of the obstacle. Proton images provide a measure of large-scale features in the magnetic field topology, and reconstructed path-integrated magnetic field maps from these images suggest the formation of a bow shock upstream of the wire and as a transient magnetopause. We compare features in the reconstructed fields to two-dimensional MHD simulations of the system.
description: PSFC REPORT PSFC/JA-21-34<br><br>This work was funded by the DOE, through the NNSA Center of Excellence under Grant No. DE-NA0003869, the NNSA-DP, and SC-OFES Joint Program in HEDLP, Grant No. DE-NA0002956, the NLUF Program and Rice University, Grant No. DE-NA0002722, NLUF Program, Grant No. DE-NA0002719, and through the LLE, University of Rochester by the NNSA/OICF under Cooperative Agreement Nos. DE-NA0001944 and DE-NA0003856. Partial support for this work was also provided by NASA through Einstein Postdoctoral Fellowship Grant No. PF3–140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under Contract No. NAS8–03060. This work was also partially supported by the U.S. Department of Phys. Plasmas 29, 012106 (2022); doi: 10.1063/5.0062254 Published under an exclusive license by AIP Publishing Energy under Field Work Proposal No. 57789 to Argonne National Laboratory, Subcontract No. 536203 with Los Alamos National Laboratory, and Subcontract No. B632670 with Lawrence Livermore National Laboratory to the University of Chicago. The FLASH software used in this work was developed in part by the DOE NNSA ASC- and DOE Office of Science ASCR-supported Flash Center for Computational Science at the University of Chicago. This work was also supported by the U.S. Department of Energy through the Los Alamos National Laboratory. The Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001).<br><br>If this record does not contain the full text, then the manuscript has been embargoed by the publisher thus restricting open access for 12 to 24 months after publication.