Experimental observations of microturbulence-suppressed parallel heat conduction in a weakly collisional, high-\b{eta} plasma

Year: 2026

Type: preprint

Abstract: Classical theories of heat conduction in magnetized plasma predict that thermal transport, mediated by Coulomb collisions of electrons, occurs predominantly along magnetic field lines. Recent theoretical and computational studies challenge this description for weakly collisional, magnetized plasmas in which thermal pressure dominates magnetic pressure (so-called high-\b{eta} plasmas). Such plasmas, which include the intracluster medium of galaxy clusters and inertial-confinement-fusion hot spots, are thought to be susceptible to kinetic-scale microinstabilities that can suppress parallel heat conduction. Revised theories of heat conduction accounting for these instabilities have been proposed, but experimental data with which to benchmark them are lacking. Here, we report experiments at the Orion laser facility in which the temporal evolution of temperature of a high-\b{eta}, weakly collisional plasma is sensitive primarily to the thermal conductivity along its initially quasi-laminar magnetic field. We characterize the temperature, density and magnetic field using x-ray spectroscopy and imaging, and proton imaging. Once stochastic magnetic fluctuations develop, the measured temperature evolution requires suppression of thermal conduction by at least an order of magnitude relative to classical predictions, providing the first laboratory evidence linking magnetic microturbulence with suppression of heat conduction in a high-\b{eta} plasma.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2610.08530

Authors: Vincent, T. A., Ariyathilaka, P., Creaser, L., Danson, C., Davies, R., Lamb, D., Meinecke, J., Palmer, C. A. J., Pitt, S., Poole, H., Spindloe, C., Thomas, P., Tubman, E. R., Wilson, L., Garbett, W., Gregori, G., Tzeferacos, P., Hodge, T., Bott, A. F. A.

Institutions: University of Oxford, Rutherford Appleton Laboratory, Central Laser Facility, AWE Nuclear Security Technologies, University of Chicago, Gettysburg College, Queen's University Belfast, University of Rochester, University of California, Berkeley

Language: English

Topic: Laser-Plasma Interactions and Diagnostics

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, U.S. Department of Energy, UK Research and Innovation, Office of Science, National Nuclear Security Administration, Engineering and Physical Sciences Research Council, Science and Technology Facilities Council, Central Laser Facility, Science and Technology Facilities Council, Los Alamos National Laboratory

OpenAlex ID: W7220893140