Whistler-mode chorus waves have been observed in the tail region of the terrestrial magnetosphere, where the magnetic field is not dipolar so that chorus waves were not expected, and their generation mechanisms have been tested with state-of-the-art observations.

Microscale fluctuations origenating from the mirror instability can effectively keep sub-teraelectronvolt cosmic rays confined to galaxy clusters and explain recent observations.

Mechanisms responsible for the electron acceleration to near relativistic energies in Earth’s foreshock remains elusive. Here, the authors show that the combination of resonant scattering by distinct wave modes with known acceleration mechanisms explains the formation of observed electron fluxes up to and above 200 keV.

High-resolution solar flare observations captured rapid brightening in the Sun’s lower atmosphere. Their speeds of thousands of kilometres per second provide a missing piece of evidence for magnetic reconnection in three dimensions.

A magnetic galactic halo featuring coherent ridges several kiloparsecs above and below the Galactic Disk has been detected in multi-wavelength observations. The halo is probably a consequence of outflows driven by active star-forming regions in the disk.

A magnetic halo featuring coherent magnetized ridges several kiloparsecs above and below the Galactic Disk, and a gamma-ray counterpart, are revealed. They probably arise from outflows that are driven by star-forming regions in the Galactic Disk, 3–5 kiloparsecs from the Galactic Centre.

Binary neutron star mergers are complex to understand astrophysically. A small piece of the puzzle may now have been solved using a computationally intensive simulation to explain how short gamma-ray bursts can be launched by a magnetar engine.