Cosmological magnetic fields and plasma physics in extended structures

2026-07-22

The majority of the visible, ordinary matter within the universe (baryons in form of hot plasma within galaxies and galaxy clusters) is shaped by complex, physical processes, which are still plagued by many enigmas (microscopic plasma instabilities; large scale progression of astrophysical systems). The available computational resources now opened the decade of their direct, numerical modelling. However, the treatment of magnetic fields and relativistic particles (so called cosmic rays) is still mostly ignored due to their complexity, although they are fundamental plasma components, shaping the underlying fluid properties (like viscosity and transport coefficients). Observed at all cosmic epochs (evident throughout non-thermal radiation) they harbor the potential to deliver new insights into the formation of cosmic structures. The understanding of their observable imprints (like measured structure within Faraday rotation maps, the appearance of so called radio relics and radio halos) face huge challenges, in both the complexity of the underlying models as well as the computational challenge to bridge the involved, tremendously large, spatial scales. COMPLEX will develop the numerical framework to perform for the first time simulations of galaxy clusters with high enough spatial resolution to resolve the important scales on which turbulence acts. It will develop novel and detailed sub-grid models needed to describe the proper evolution of magnetic fields, cosmic rays and associated transport processes. Self consistently coupled to the important astrophysical processes this will allow to identify the key processes responsible for shaping the detailed composition of the largest fraction of the visible matter in the universe. Combined for the first time, this will deliver key knowledge and innovative models to interpret the ongoing and future astronomical surveys which, due to their enlarged wavelength coverage and sensitivity, are entering largely unexplored territory.

Germany

2026-02-15