Behavior and Utility of Flow or Turbulence in Compressing Plasma
Seth Davidovits | 20-ERD-058
Evidence suggests the plasma in both laser- and magnetically-driven compressions can contain substantial flow that is not associated with the compression itself. To model and explain such experiments, we must both predict the behavior of this (possibly turbulent) nonradial flow and assess its impacts. These impacts can be many and important, for example, such flows can substantially degrade fusion-ignition experiments through multiple mechanisms: mixing of nonfuel into the fusion fuel, perturbing the inertial confinement, changing transport properties, or wasting limited compression (drive) energy. Modeling such flows is generally difficult, requiring highly resolved simulations, which limits understanding.
Here we study compressing flow and turbulence, in part by developing and exploiting novel simulation frameworks for such flows. This allows us to develop new modeling, including quasi "equations of state" (EOS) for compressing turbulence, significantly enhancing our ability to predict these flows. Our results greatly speed up modeling of certain degradation sources in inertial fusion implosions. We develop a new experimental platform for generating and studying turbulence and create and validate a new experimental analysis for detecting these difficult-to-measure flows in experiments. Additionally, we show how discoveries herein could lead to the development of a novel compression design for achieving fusion, X-ray generation, or extreme density and temperature states.
This research supports the NNSA stockpile-stewardship mission and enhances the Laboratory's competency in high-energy-density physics. This project shows how to utilize new understandings of the fundamental properties of plasma flow to harness turbulent energy. Successful development could be game changing for producing fusion or bursts of x-rays, both important components of Laboratory missions. The fundamental understanding developed in this research is benefiting not only current inertial-confinement-fusion efforts, but, more generally, connects the regimes achievable on the National Ignition Facility (NIF) to important questions in turbulence that are encountered in a variety of settings, including stockpile stewardship and astrophysics.
Publications, Presentations, and Patents
Davidovits, S., et al. 2022. "Modeling Ablator Grain Structure Impacts in ICF Implosions." Accepted. Physics of Plasmas.
Davidovits, S., et al. 2022. "Turbulence Generation by Shock Interaction with a Highly Nonuniform Medium." Physical Review E 105, no. 6: 065206 (2022); doi.org/10.1103/PhysRevE.105.065206.
Dhawalikar, S., et al. 2022. "The Driving Mode of Shock-Driven Turbulence." Monthly Notices of the Royal Astronomical Society 514, no. 2: 1782-1800 (2022); doi: 10.1093/mnras/stac1480.
Li, G., and S. Davidovits. 2021. "LIGR (Linear Grains) Version 1.0." https://github.com/LLNL/LIGR.
Davidovits, S., et al. 2021. "Hydrodynamic-Dissipation Relation for Characterizing Flow Stagnation." Physical Review E 103, no. 6: 063204 (2021); doi.org/10.1103/PhysRevE.103.063204.
Davidovits, S., and N. J. Fisch. 2020. "Preferential Turbulence Enhancement in Two-Dimensional Compressions." Physical Review E 102, no. 5: 053213 (2020); doi: 10.1103/PhysRevE.102.053213.
Davidovits, S. 2022. "Turbulence Augmented Applied Magnetic Field in Compressions." Poster, 64th Annual Meeting of APS Division of Plasma Physics, Spokane, WA, October 2022.
Li, R., and S. Davidovits. 2022. "VISAR Inference for NIF Star Formation Experiments." Talk. LLNL Defense Science and Technology Internship End of Summer Talks, Livermore, CA. August 2022.
Davidovits, S. 2022. "Modeling and Fuel-Ablator-Mixing Dynamics for Perturbations Driven by Small-Scale Ablator Inhomogeneity." Poster, LLNL Design Physics Poster Session, Livermore, CA. May 2022.
Davidovits, S., et al. 2021. "Carbon Grain Structure Impacts on Fuel-Ablator Mixing." Talk, 63rd Annual Meeting of APS Division of Plasma Physics, Pittsburgh, PA. November 2022.
Li, G., and S. Davidovits. 2021. "Analytic Predictions of Grain Effects on Shock Behavior." Talk, LLNL HEDP Summer Student End of Summer Talks, Virtual. August 2021.
Davidovits, S. 2021. "Turbulence in High-Energy-Density Experiments: inference and Generation." Invited talk, Journal of Plasma Physics Frontiers of Plasma Physics Colloquium, Virtual. May 2021.
Davidovits, S., et al. 2021. "Laser Experiments on the Turbulent Formation of Stars." Invited talk, NIF and JLF User Group Meeting, Virtual. February 2021.
Davidovits, S. 2020. "A Hydrodynamic Lengthscale for Characterizing Stagnation." Poster, 62nd Annual Meeting of APS Division of Plasma Physics, Virtual. November 2020.
Zhang, M., et al. 2020. "Shock-TurbulenceInteraction with Plasma Viscosity." Poster, 62nd Annual Meeting of APS Division of Plasma Physics, Virtual. November 2020.
Zhang, M., et al. 2020. "Shock-Turbulence Interaction with Plasma Viscosity." Talk, LLNL HEDP Summer Student End of Summer Talks, Virtual. August 2020.
Davidovits, S.. 2019. "Freezing Turbulent Magnetic Field." Invited talk, Weizmann Institute of Science, Rehovot, Israel, December 2019.
Davidovits, S., and N. J. Fisch. 2019. "Turbulent Energy Behavior in 2D vs 3D Compressions." Poster, 61st Annual Meeting of APS Division of Plasma Physics, Fort Lauderdale, FL. October 2019.