arXiv subjects

B. Coleman

Publications and source records attributed to B. Coleman.

3 recordsLinked to original sources

arXiv2026

Science of High Resolution X-ray Imaging

This report summarizes potential studies of the Hi-ReX Science Analysis Group for an Ultra-High Angular Resolution X-ray Observatory. Many potential science cases are presented, spanning a range of astrophysical topics from solar system planets and exoplanets to supermassive black holes and cosmology. These cases demonstrate the value of X-ray imaging beyond current capabilities with an aim toward milli-arcsecond and micro-arcsecond angular scales. There is an imaging gap between the current capability of the best X-ray imaging telescope, the Chandra X-ray Observatory, compared to that of instruments across the electromagnetic spectrum. Next-generation, ultra-high angular resolution X-ray imaging will close this gap and transform our understanding of the universe and fundamental physics.

astro-ph.HE↗

arXiv2022

Dynamics of nanosecond laser pulse propagation and of associated instabilities in a magnetized underdense plasma

The propagation and energy coupling of intense laser beams in plasmas are critical issues in laser-driven inertial confinement fusion. Applying magnetic fields to such a setup has been evoked to enhance fuel confinement and heating, and mitigate laser energy losses. Here we report on experimental measurements demonstrating improved transmission and increased smoothing of a high-power laser beam propagating in an underdense magnetized plasma. We also measure enhanced backscattering, which our simulations show is due to hot electrons confinement, thus leading to reduced target preheating.

physics.plasm-ph↗

arXiv2020

Observations of Pressure Anisotropy Effects within Semi-Collisional Magnetized-Plasma Bubbles

Magnetized plasma interactions are ubiquitous in astrophysical and laboratory plasmas. Various physical effects have been shown to be important within colliding plasma flows influenced by opposing magnetic fields, however, experimental verification of the mechanisms within the interaction region has remained elusive. Here we discuss a laser-plasma experiment whereby experimental results verify that Biermann battery generated magnetic fields are advected by Nernst flows and anisotropic pressure effects dominate these flows in a reconnection region. These fields are mapped using time-resolved proton probing in multiple directions. Various experimental, modelling and analytical techniques demonstrate the importance of anisotropic pressure in semi-collisional, high-$\beta$ plasmas, causing a reduction in the magnitude of the reconnecting fields when compared to resistive processes. Anisotropic pressure dynamics are crucial in collisionless plasmas, but are often neglected in collisional plasmas. We show pressure anisotropy to be essential in maintaining the interaction layer, redistributing magnetic fields even for semi-collisional, high energy density physics (HEDP) regimes

physics.plasm-ph↗