Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas
Science Advances 8, 10 (2022)
Abstract:
In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter to colder regions and the coefficient of thermal conduction given by Spitzer’s theory. However, this theory breaks down in magnetized, turbulent, weakly collisional plasmas, although modifications are difficult to predict from first principles due to the complex, multiscale nature of the problem. Understanding heat transport is important in astrophysical plasmas such as those in galaxy clusters, where observed temperature profiles are explicable only in the presence of a strong suppression of heat conduction compared to Spitzer’s theory. To address this problem, we have created a replica of such a system in a laser laboratory experiment. Our data show a reduction of heat transport by two orders of magnitude or more, leading to large temperature variations on small spatial scales (as is seen in cluster plasmas).
Improved Characterization of the Astrophysical Muon–neutrino Flux with 9.5 Years of IceCube Data
The Astrophysical Journal American Astronomical Society 928:1 (2022) 50
Light-shining-through-wall axion detection experiments with a stimulating laser
Physical Review D - Particles, Fields, Gravitation and Cosmology American Physical Society 105 (2022) 035031
Abstract:
The collision of two real photons can result in the emission of axions. We investigate the performance of a modified light-shining-through-wall (LSW) axion search aiming to overcome the large signal suppression for axion masses ma ≥ 1 eV. We propose to utilize a third beam to stimulate the reconversion of axions into a measurable signal. We thereby find that with currently available high-power laser facilities we expect bounds at axion masses between 0.5–6 eV reaching gaγγ ≥ 10−7 GeV−1. Combining the use of optical lasers with currently operating x-ray free electron lasers, we extend the mass range to 10–100 eV.
Search for High-Energy Neutrino Emission from Galactic X-ray Binaries with IceCube
(2022)
Time-resolved hadronic particle acceleration in the recurrent Nova RS Ophiuchi
(2022)