Laboratory astroparticle physics

Abstract:

Observations of transient phenomena like Gamma-Ray Bursts (GRBs), Fast Radio Bursts (FRBs), stellar flares and explosions (novae and supernovae), combined with the detection of novel cosmic messengers like high-energy neutrinos and gravitational waves has revolutionized astrophysics over the last years. The discovery potential of both ulti-messenger and multi-wavelength follow-up observations as well as serendipitous observations could be maximized with a novel tool which allows for quickly acquiring an overview over relevant information associated with each new detection. Here we present Astro-COLIBRI, a novel and comprehensive platform for this challenge. Astro-COLIBRI's architecture comprises a public RESTful API, real-time databases, a cloud-based alert system and a website as well as apps for iOS and Android as clients for users. Astro-COLIBRI evaluates incoming messages of astronomical observations from all available alert streams in real time, filters them by user specified criteria and puts them into their MWL and MM context. The clients provide a graphical representation with an easy to grasp summary of the relevant data to allow for the fast identification of interesting phenomena, provides an assessment of observing conditions at a large selection of observatories around the world, and much more. Here the key features of Astro-COLIBRI are presented. We outline the architecture, summarize the used data resources, and provide examples for applications and use cases. Focussing on the high-energy domain, we'll discuss the use of the platform in searches for high-energy gamma-ray counterparts to high-energy neutrinos, gamma-ray bursts and gravitational waves.Comment: Proceedings 38th International Cosmic Ray Conference (ICRC2023

Abstract:

An x-ray radiography technique based upon phase contrast imaging using a lithium fluoride detector has been demonstrated for goals of high energy density physics experiments. Based on the simulation of propagation an x-ray free-electron laser beam through a test-object, the visibility of phase-contrast image depending on an object-detector distance was investigated. Additionally, the metrological capabilities of a lithium fluoride crystal as a detector were demonstrated.

Abstract:

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-β 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.