Revealing a Systematic High-latitude Current Sheet at Jupiter

TL;DR

This study reveals a persistent high-latitude current sheet at Jupiter's nightside, challenging traditional magnetotail models based on Earth, and provides new insights into magnetospheric structures of rapidly rotating planets.

Contribution

Using Juno data, we identified a high-latitude current sheet at Jupiter, indicating a need to revise existing planetary magnetotail models.

Findings

Detected a high-latitude current sheet above 40° magnetic latitude near midnight.

The structure contains internally sourced oxygen and sulfur ions.

Magnetic signatures are opposite to the equatorial current sheet bend-back.

Abstract

Based on models derived from Earth's magnetotail, other planets with dipole magnetic fields, including Mercury, Jupiter, and Saturn, were expected to possess similar magnetotail configurations. In this traditional picture, the majority of plasma is confined near the magnetic equator within a plasma sheet (or plasma disc), whereas higher-latitude regions feature strong magnetic fields that are open to the solar wind, forming magnetospheric lobes. However, auroral observations and recent simulations have shown that Jupiter's magnetic topology differs markedly from this picture, particularly in its high-latitude regions where magnetic field lines are predominantly closed. This discrepancy calls for a re-examination of high-latitude magnetospheric structure at Jupiter. Here, using Juno measurements acquired between 2016 and 2022, we show that Jupiter's nightside high latitudes host a persistent current-sheet-like structure above about 40 degrees magnetic latitude near midnight. This structure contains internally sourced oxygen and sulfur ions and exhibits azimuthal magnetic signatures opposite to the bend-back of the equatorial current sheet. These findings indicate that the canonical picture of planetary magnetotail architecture requires revision. Our results provide new insight into the architecture of rapidly rotating magnetospheres and offer a framework for interpreting magnetospheric structures at exoplanets.