Laser-produced plasmas as drivers of laboratory collisionless quasi-parallel shocks

Abstract

The creation of a repeatable collisionless quasi-parallel shock in the laboratory would provide a valuable platform for experimental studies of space and astrophysical shocks. However, conducting such an experiment presents substantial challenges. Scaling the results of hybrid simulations of quasi-parallel shock formation to the laboratory highlights the experimentally demanding combination of dense, fast, and magnetized background and driver plasmas required. One possible driver for such experiments are high-energy laser-produced plasmas (LPPs). Preliminary experiments at the University of California Los Angeles have explored LPPs as drivers of quasi-parallel shocks by combining the Phoenix Laser Laboratory [Niemann et al. Journal of Instrumentation, 7, 2012] with the Large Plasma Device (LAPD) [Gekelman et al. Review of Scientific Instruments, 87, 2016]. Beam instabilities and waves characteristic of the early stages of shock formation are observed, but spatial dispersion of the laser-produced plasma prematurely terminates the process. This result is illustrated by experimental measurements and Monte-Carlo calculations of LPP density dispersion. The experimentally-validated Monte-Carlo model is then applied to evaluate several possible approaches to mitigating LPP dispersion in future experiments.

Hybrid Paricle-in-Cell Simulations of Electromagnetic Coupling and Waves From Streaming Burst Debris

“…It is noteworthy that this situation has been observed in a laserplasma lab experiment. 22 The simulation of Fig. 8 is similar to the previous calculation, but with the finite beam length Λ x = 500 d i .…”

“…21 The NRI may also be within the reach of existing -or slightly modified -experimental platforms. 20,22 Modeling the coupling of debris ions from an explosion to the background is challenging because it is difficult to resolve the relatively small fraction 23 of debris that escapes parallel to the magnetic field and because the coupling occurs over long length scales of hundreds of ion inertial lengths. Retaining ion kinetics in such a large system is possible when the electrons may be treated as a neutralizing background, requiring only a generalized Ohm's law to couple the electron fluid to the kinetic ions.…”

The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

“…( 2018 ) and Heuer et al. ( 2020 ) performed experiments on the ion/ion-beam instabilities behind shock formation, particularly of quasi-parallel shocks. At another laser facility (Boehly et al.…”

Two-Dimensional Thomson Scattering in Laser-Produced Plasmas

“…Measurements of the spatial variation of density and temperature in laser-produced plasmas (LPP) are crucial for the interpretation of laboratory experiments on perpendicular [8,9] and parallel [10,11] collisionless shocks [12,13] and related instabilities [14], diamagnetic cavities [15], magnetic reconnection [16], collisionless momentum transfer [17,18], artificial magnetospheres [19], or the generation of spontaneous magnetic fields via the Biermann battery [20,21]. However, with conventional Thomson scattering setups, only limited data points can be obtained for each configuration of the experiment.…”