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Ionospheric escape of $${\bf{H}}_{\mathbf{3}}^{\mathbf{+}}$$ from Jupiter’s polar regions
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DOI:10.1038/s41550-026-02950-2.png)
Abstract
En 中文
Trihydrogen cations (
$${{\rm{H}}}_{3}^{+}$$
), a key diagnostic of atmospheric energy balance, are produced through ionization by solar radiation and particle impacts in hydrogen-rich planetary atmospheres. At Jupiter,
$${{\rm{H}}}_{3}^{+}$$
is produced most efficiently in the auroral region through electron precipitation and has a leading role in magnetosphere–ionosphere coupling by regulating ionospheric conductance. Previously, the properties of
$${{\rm{H}}}_{3}^{+}$$
have been determined from remote sensing, with plasma parameters retrieved from its infrared emissions, although these measurements are limited by line-of-sight integration and restricted altitude resolution. Here we report the unambiguous, direct in situ detection of
$${{\rm{H}}}_{3}^{+}$$
plasma in the auroral region. Furthermore, intermittent
$${{\rm{H}}}_{3}^{+}$$
outflows are measured high above the ionosphere, with upwards velocities exceeding Jupiter’s escape speed, confirming atmospheric escape of
$${{\rm{H}}}_{3}^{+}$$
. We propose that
$${{\rm{H}}}_{3}^{+}$$
outflow originates in the auroral upwards electric current region, initially triggered by plasma-wave interactions and subsequently accelerated by the electric potential structure above the ionosphere. This study reveals a
$${{\rm{H}}}_{3}^{+}$$
-mediated pathway for mass and energy transfer between the ionosphere and magnetosphere of Jupiter, constituting an atmospheric escape with a loss rate of order 1026 s−1. Similar mechanisms may operate at other planets with infrared aurorae and strong magnetic fields. In Jupiter’s polar region,
$${{\rm{H}}}_{3}^{+}$$
has a key role in atmospheric heating and ionospheric conductance. Juno measurements show in situ detection of
$${{\rm{H}}}_{3}^{+}$$
and provide direct evidence of its escape, revealing a pathway for energy transfer between the magnetosphere and the ionosphere.
Journal
IF:
14.3
Papers:
2.8K
Citations:
1.3W
