Design of experiments on the Orion Laser to measure thermal transport in high-𝜷, weakly collisional plasma

The study of thermal transport in plasmas is necessary for understanding many extreme environments observed in the Universe, including the intracluster medium (ICM) of galaxy clusters and in inertial-confinement fusion (ICF) experiments. Theoretical modelling of transport in these systems is challenging due to the multi-scale nature of the physics that determines this transport. A recent experiment performed using the National Ignition Facility (NIF) showed that thermal conductivity induced by electron transport in a high-𝛽, weakly collisional, turbulent plasma was suppressed by two orders of magnitude compared to the classical Spitzer value. However, the complicated field geometries and flows present in the plasma made it difficult to pinpoint the cause of the suppression. One possible mechanism considered was suppression induced by microinstabilities, notably the whistler heat flux instability which has been predicted to suppress conduction for similar plasmas. Making new experimental measurements of thermal transport in such plasmas, with simpler magneticfield geometries, could help constrain theoretical models more tightly.