Corotating Magnetic Reconnection Site in Saturn's Magnetosphere

TL;DR

This paper presents a 3D model of a long-lasting, corotating magnetic reconnection site in Saturn's magnetosphere, driven internally, affecting current sheet expansion and electron acceleration, with implications for planetary and astrophysical plasma dynamics.

Contribution

It introduces the concept of a long-lived, internally driven corotating reconnection site in Saturn's magnetosphere, differing from Earth's reconnection processes.

Findings

Reconnection site lasted longer than one Saturn rotation period

Corotating reconnection drives current sheet expansion

It can produce Fermi acceleration of electrons

Abstract

Using measurements from the Cassini spacecraft in Saturn's magnetosphere, we propose a 3D physical picture of a corotating reconnection site, which can only be driven by an internally generated source. Our results demonstrate that the corotating magnetic reconnection can drive an expansion of the current sheet in Saturn's magnetosphere and, consequently, can produce Fermi acceleration of electrons. This reconnection site lasted for longer than one of Saturn's rotation period. The long-lasting and corotating natures of the magnetic reconnection site at Saturn suggest fundamentally different roles of magnetic reconnection in driving magnetospheric dynamics (e.g., the auroral precipitation) from the Earth. Our corotating reconnection picture could also potentially shed light on the fast rotating magnetized plasma environments in the solar system and beyond.