Gianluca Gregori

Abstract:

Cosmic rays (CRs) play a pivotal role in shaping the thermal and dynamical properties of astrophysical environments, such as galaxies and galaxy clusters. Recent observations suggest a stronger confinement of CRs in certain astrophysical systems than predicted by current CR-transport theories. Here, we show that the incorporation of microscale physics into CR-transport models can account for this enhanced CR confinement. We develop a theoretical description of the effect of magnetic microscale fluctuations originating from the mirror instability on macroscopic CR diffusion. We confirm our theory with large-dynamical-range simulations of CR transport in the intracluster medium (ICM) of galaxy clusters and kinetic simulations of CR transport in micromirror fields. We conclude that sub-teraelectronvolt CR confinement in the ICM is far more effective than previously anticipated on the basis of Galactic-transport extrapolations. The transformative impact of micromirrors on CR diffusion provides insights into how microphysics can reciprocally affect macroscopic dynamics and observable structures across a range of astrophysical scales.

Abstract:

Data used for the generation of the figures

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Data for the plots in Measurement of turbulent velocity and bounds for thermal diffusivity in laser shock compressed foams by X-ray photon correlation spectroscopy

Abstract:

Discussion about the new edition of the Catalogue on the Latin epigraphy from Ostia, with the publication of over 2000 sepulchral inscriptions. They shed light on the work of the stonecutters, and on the various types of errors that they used to commit, or on onomastic peculiarities.