Survey of Juno Observations in Jupiter's Plasma Disk: Density

Huscher, Ezra L.; Bagenal, F.; Wilson, R. J.; Allegrini, F.; Ebert, R. W.; Valek, P. W.; Szalay, J. R.; McComas, D. J.; Connerney, J. E. P.; Bolton, S. J.; Levin, S. M.

doi:10.1029/2021ja029446

Cited by 28 publications

(65 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, the distance between the TEB and MAW is seen to decrease in the 270–290° range. Although Io's TEB and MAW are expected to merge near λ ∼ 285°, the longitude at which they are observed to merge is known to vary, likely because of the plasma sheet variability, which increases as a function of the radial distance (e.g., Huscher et al., 2021). The amplitude of the field‐aligned current was estimated to be 4.2 ± 1.2 kA.…”

Section: Discussionmentioning

confidence: 99%

A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint

Hue

Szalay

Greathouse

et al. 2022

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

Jupiter's satellite auroral footprints are a manifestation of the satellite‐magnetosphere interaction of the Galilean moons. Juno's polar elliptical orbit enables crossing the magnetic flux tubes connecting each Galilean moon with their associated auroral emission. Its payload allows measuring the fields and particle population in the flux tubes while remotely sensing their associated auroral emissions. During its thirtieth perijove, Juno crossed the flux tube directly connected to Ganymede's leading footprint spot, a unique event in the entire Juno prime mission. Juno revealed a highly‐structured precipitating electron flux, up to 316 mW/m2, while measuring both a small perturbation in the magnetic field azimuthal component and small Poynting flux with an estimated total downward current of 4.2 ± 1.2 kA. Based on the evolution of the footprint morphology and the field and particle measurements, Juno transited for the first time through a region connected to the transhemispheric electron beam of the Ganymede footprint.

show abstract

Section: Discussionmentioning

confidence: 99%

A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint

Hue

Szalay

Greathouse

et al. 2022

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Magnetic fields in the current sheet have been modeled (e.g., Acuna & Ness, 1976;Connerney et al, 1981Connerney et al, , 2018Connerney et al, , 2020, based on which the current system (e.g., Khurana, 2001) and mass flow (e.g., Khurana & Kivelson, 1993;Vasyliunas, 1983) in the magnetosphere have been investigated. Besides, charged particles have also been investigated and modeled (but generally limited to the inner magnetosphere 𝐴𝐴 𝐴𝐴 𝐴 30 𝐴𝐴 R𝐽𝐽 ) (e.g., Bridge et al, 1979;de Soria-Santacruz et al, 2016;Huscher et al, 2021;Khurana et al, 2004;Kim et al, 2020;Krupp et al, 2004;Mauk & Krimigis, 1987;Wang et al, 2021). The flux of these particles is found to decrease with increasing energy, radial distances, and the distances to the center of the current sheet.…”

mentioning

confidence: 99%

Statistics on Jupiter’s Current Sheet With Juno Data: Geometry, Magnetic Fields and Energetic Particles

et al. 2021

View full text Add to dashboard Cite

Jupiter, the fifth planet from the sun, has the strongest intrinsic magnetic field among planets in the solar system. The interplay between this magnetic field and the solar wind results in a magnetosphere extending from the topside of Jupiter's atmosphere/ionosphere to beyond 𝐴𝐴 𝐴𝐴∼ 100 𝐴𝐴 R𝐽𝐽 (1 𝐴𝐴 R𝐽𝐽 = 𝐴𝐴 ∼ 71,400 km, Jupiter radii; hereinafter, 𝐴𝐴 𝐴𝐴 represents the radial distance to the Jupiter) (Bagenal et al., 2007). Jupiter's magnetosphere is filled with plasma originating from various sources, including the solar wind, Jupiter's atmosphere/ionosphere, and Jupiter's moons. Among these sources, the moon Io, which supplies 𝐴𝐴 ∼ 1 ton plasma per second to the magnetosphere (e.g., Thomas et al., 2004), serves as the dominant one (e.g., Bolton et al., 2015). After entering the magnetosphere, plasma from Io (and other sources) is picked up by the magnetospheric corotating electric fields and corotates with Jupiter with a period of 9.92 hr. The corotation, in turn, induces a centrifugal force on plasma. This force tends to pull plasma radially outward against the magnetic forces, leading to the deformation of Jupiter's dipole-like magnetic fields (e.g., Hill et al., 1974). The deformation is reinforced by the plasma pressure gradient and anisotropy, which, as suggested by later observational and modeling work (e.g., Caudal, 1986;Mauk & Krimigis, 1987;Paranicas et al., 1991), even play a dominant role in balancing the magnetic forces. As a final result of the force balance, a current sheet is formed in Jupiter's middle and outer magnetosphere (Vasyliunas, 1983).Because of Jupiter's dipole tilts ( ∼10 • ), Jupiter's current sheet is generally displaced from Jupiter's rotational equator (Khurana, 1992;Khurana & Schwarzl, 2005;Connerney et al., 1981). As a result of this displacement and Jupiter rotation, a spacecraft in Jupiter's magnetosphere would periodically cross the current sheet. These periodical crossings manifest as a series of magnetic field reversals in magnetic field data (e.g., Connerney et al., 1981;Khurana & Schwarzl, 2005). According to previous observations, magnetic field reversals can be detected from 𝐴𝐴 𝐴𝐴∼ 10 𝐴𝐴 R𝐽𝐽 to almost the magnetopause (e.g., Connerney et al., 1981;Khurana & Schwarzl, 2005), suggesting the existence of the current sheet in the most of the equatorial regions of Jupiter's magnetosphere. Besides its huge size and notability in observations, the current sheet plays a Abstract Jupiter's magnetosphere contains a current sheet of huge size near its equator. The current sheet not only mediates the global mass and energy cycles of Jupiter's magnetosphere, but also provides a site for many localized dynamic processes, such as reconnection and wave-particle interaction. To correctly evaluate its role in these processes, a statistical description of the current sheet is required. To this end, here we conduct statistics on Jupiter's current sheet, by using four-year Juno data obtained in the 20-100 Jupiter radius, 0-6 local time magnetosphere. The statistics show the thickness of th...

show abstract

“…Huscher et al. (2021) reported a depleted plasma sheet between 30 and 50

{R}_{J}

during orbit 12 and linked this to the multiple reconnection events observed during orbit 11 by Vogt et al. (2020).…”

Section: Discussionmentioning

confidence: 90%

“…They also noted that the UV aurora was dimmer during orbit 7 than orbit 5. Huscher et al (2021) reported a depleted plasma sheet between 30 and 50 𝐴𝐴 𝐴𝐴𝐽𝐽 during orbit 12 and linked this to the multiple reconnection events observed during orbit 11 by Vogt et al (2020). The long-term variability of the Jovian magnetosphere may be related to other visible changes such as in the strength of the magnetodisc current sheet and location of the Jovian aurora, which could occur due to changes in mass loading from Io rather than external solar wind conditions (Vogt et al, 2017).…”

Section: Orbit-by-orbit Variability and Comparison With Other Studiesmentioning

confidence: 91%

Properties of Ion‐Inertial Scale Plasmoids Observed by the Juno Spacecraft in the Jovian Magnetotail

et al. 2022

View full text Add to dashboard Cite

We expand on previous observations of magnetic reconnection in Jupiter's magnetosphere by constructing a survey of ion‐inertial scale plasmoids in the Jovian magnetotail. We developed an automated detection algorithm to identify reversals in the Bθ ${B}_{\theta }$ component and performed the minimum variance analysis for each identified plasmoid to characterize its helical structure. The magnetic field observations were complemented by data collected using the Juno Waves instrument, which is used to estimate the total electron density, and the JEDI energetic particle detectors. We identified 87 plasmoids with “peak‐to‐peak” durations between 10 and 300 s. Thirty‐one plasmoids possessed a core field and were classified as flux‐ropes. The other 56 plasmoids had minimum field strength at their centers and were termed O‐lines. Out of the 87 plasmoids, 58 had in situ signatures shorter than 60 s, despite the algorithm's upper limit being 300 s, suggesting that smaller plasmoids with shorter durations were more likely to be detected by Juno. We estimate the diameter of these plasmoids assuming a circular cross section and a travel speed equal to the Alfven speed in the surrounding lobes. Using the electron density inferred by Waves, we contend that these plasmoid diameters were within an order of the local ion‐inertial length. Our results demonstrate that magnetic reconnection in the Jovian magnetotail occurs at ion scales like in other space environments. We show that ion‐scale plasmoids would need to be released every 0.1 s or less to match the canonical 1 ton/s rate of plasma production due to Io.

show abstract

Survey of Juno Observations in Jupiter's Plasma Disk: Density

Cited by 28 publications

References 52 publications

A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint

A Comprehensive Set of Juno In Situ and Remote Sensing Observations of the Ganymede Auroral Footprint

Statistics on Jupiter’s Current Sheet With Juno Data: Geometry, Magnetic Fields and Energetic Particles

Properties of Ion‐Inertial Scale Plasmoids Observed by the Juno Spacecraft in the Jovian Magnetotail

Contact Info

Product

Resources

About