Magnetotail plasmoid eruption: Interplay of instabilities and reconnection

Abstract

Rapid plasma eruptions explosively release energy in the Earth’s magnetosphere, at the Sun, and solar system planets. At Earth, these eruptions, termed plasmoids, occur in the magnetospheric nightside, and are associated with the sudden brightening of the aurora. The chain of events leading to the plasmoid is one of the longest-standing unresolved questions in space physics. Two competing paradigms, based on magnetic reconnection or kinetic instabilities, are proposed to explain the course of events. We report results of a major technological achievement modelling the Earth’s magnetosphere at realistic scales, with sufficient spatiotemporal resolution, and resolving ion-kinetic physics, and thereby capturing physics essential to both paradigms. We show that both magnetic reconnection and kinetic instabilities are required to induce a global topological reconfiguration of the magnetotail, thereby combining the seemingly contradictory paradigms. Our results show that magnetic reconnection creates local plasmoids that are combined into a tail-wide structure by a current sheet disruption in the center tail. Large-scale current sheet flapping, caused by a drift kink instability and driven by reconnection-generated ions, leads to the current disruption. Our results help to understand plasma eruptions ubiquitous in space plasmas, guide spacecraft constellation mission design, and lead to improved understanding of space weather. We also contemplate the future direction of models within the solar system plasma physics and heliophysics discipline.