The ion-scale refers to a spatial scale in plasma physics that is on the order of the gyroradius of an ion in a plasma. It is typically characterized by scales on the order of a few centimeters to a few meters. Research on the ion-scale focuses on studying the behavior of ions in plasmas, including their motion, interactions with electromagnetic fields, and collective effects. This research is important for understanding processes such as turbulence, heating, and particle acceleration in plasmas, which can have applications in areas such as fusion energy research and space physics. Studies on the ion-scale often use advanced experimental techniques and numerical simulations to investigate these processes in detail.