Journal Article

Jovian Magnetospheric Injections Observed by the Hubble Space Telescope and Juno

Connerney, J. E. P., Provan, G., Allegrini, F., Gladstone, G. R., Haggerty, D. K., Bonfond, B., Grodent, D., Wilson, R. J., Clark, G. B., Clarke, J. T., Ebert, R. W., Cowley, S. W. H., Orton, G. S., Bagenal, F., Nichols, J. D., Mauk, B.

2023

Overview

We compare Hubble Space Telescope observations of Jupiter's FUV auroras with contemporaneous conjugate Juno in situ observations in the equatorial middle magnetosphere of Jupiter. We show that bright patches on and equatorward of the main emission are associated with hot plasma injections driven by ongoing active magnetospheric convection. During the interval that Juno crossed the magnetic field lines threading the complex of auroral patches, a series of energetic particle injection signatures were observed, and immediately prior, the plasma data exhibited flux tube interchange events indicating ongoing convection. This presents the first direct evidence that auroral morphology previously termed “strong injections” is indeed a manifestation of magnetospheric injections, and that this morphology indicates that Jupiter's magnetosphere is undergoing an interval of active iogenic plasma outflow. Plain Language Summary Auroras, known as the “Northern (or Southern) Lights” on Earth, are spectacular manifestations of energetic processes occurring in the space environment of a planet. The behavior of Jupiter's magnetosphere is dominated by the planet's rapid rotation, along with the centrifugally‐driven outflow of plasma (ionized gas) originating from active volcanoes on the moon Io. A prominent auroral feature on Jupiter has for many years been interpreted as a sign that Jupiter's magnetosphere is undergoing active convection, in which plasma from Io “falls” away from the planet, to be replaced by hot, relatively empty “bubbles” known as injections, moving inward. This feature comprises prominent patches of bright emission that are often observed in Jupiter's auroras, though the evidence associating them with injections has been largely circumstantial. Here we show that the NASA Juno spacecraft flew through such injections in the equatorial magnetosphere on magnetic field lines mapping to a cluster of auroral patches as observed by HST. The Juno data also indicated the interval was characterized by signatures of convection and outflow of plasma originating from Io. This demonstrates that auroral patches are signatures of injections, and that auroral emissions are an important tool for diagnosing the behavior of planetary magnetospheres. Key Points Bright FUV auroral patches on Jupiter are associated with magnetospheric injections and magnetospheric convection Hubble Space Telescope and Juno equatorial data show a cluster of patches is magnetically conjugate with energetic particle injections The interval also exhibits flux tube interchange and lagging magnetic field associated with plasma mass outflow

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: Aerospace environments / aurora / Aurorae / Auroral emissions / Auroras / Aérospatiale, astronomie & astrophysique / Convection / dynamics / Earth and Planetary Sciences (all) / Emission / Energetic particles / General Earth and Planetary Sciences / Geophysics / Hot plasmas / Hubble Space Telescope / Hubble space telescopes / In-situ observations / Injection / injections / Jupiter / Jupiter probes / Jupiters / Magnetic field / Magnetic field line / Magnetic fields / magnetosphere / Magnetospheric convection / Magnetospherics / Morphology / Outflow / Particle injection / Physical, chemical, mathematical & earth Sciences / Physique, chimie, mathématiques & sciences de la terre / Planetary magnetospheres / Planetary rotation / Planets / Plasma / Plasma convection / Plasma injection / Rotating plasmas / Signatures / Space science, astronomy & astrophysics / Space telescopes / Spacecraft