Schematic of the experimental configuration for the study of particle acceleration in magnetized shocks at NIF. Laser irradiation of a carbon foil drives a piston into a magnetized hydrogen plasma. Optical Thomson Scattering (OTS), Xray imaging (GXD) and particle spectrometers (NEPPS) are used to characterize the shock structure and particle acceleration for variable magnetizations and inclinations of the piston flow with respect to the ambient magnetic field.
Astrophysical collisionless shocks are among the most powerful particle accelerators in the Universe. The objectives of this research are to perform large-scale first-principles simulations of magnetized collisionless shocks to address important longstanding questions associated with energy partition and particle acceleration.
Generated by violent interactions of supersonic plasma flows with the ambient medium, shock waves are observed to amplify magnetic fields and to accelerate electrons and ions to highly relativistic speeds. Recent developments in laboratory high-energy-density (HED) laser-plasma experiments are now opening for the first time the opportunity to probe the microphysics and particle acceleration mechanisms of magnetized collisionless shocks in conditions relevant to high-energy astrophysical environment.
The objectives of this research are to perform large-scale first-principles simulations of magnetized collisionless shocks to address important longstanding questions associated with energy partition and particle acceleration: “What are the processes that mediate the onset of magnetic turbulence in the shock and does it decay?”, “What is the difference between electron and ion thermalization at the shock?”, “What is the injection process for particle acceleration at the shock front, and what is the efficiency?” A transformative advance in the ability to address these questions requires the combination of three-dimensional, high dynamic range, fully kinetic simulations and controlled laboratory experiments where numerical findings can be tested and used to improve theoretical models and the understanding of observations, which is at the focus of this project. The fundamental understanding of particle acceleration in plasmas to be provided by this project is central to DOE’s mission in Discovery Plasma Science. The results of this research are expected to have a significant impact on unveiling long-standing questions behind cosmic plasma accelerators, in advancing the understanding of interpenetrating magnetized HED plasmas, and in generating new ideas for efficient laboratory accelerators. Finally, the tight connection between the planned simulations and experimental programs on the National Ignition Facility will also enable the important benchmark of widely used numerical plasma models in magnetized HED conditions of relevance to DOE programs