Juno Observations of Ion‐Inertial Scale Flux Ropes in the Jovian Magnetotail

Sarkango, Yash; Slavin, J. A.; Jia, Xianzhe; DiBraccio, G. A.; Gershman, D. J.; Connerney, J. E. P.; Kurth, W. S.; Hospodarsky, G. B.

doi:10.1029/2020gl089721

Cited by 7 publications

(8 citation statements)

References 55 publications

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“…In addition to the mass cycle, the current sheet also mediates the angular momentum and energy transfer from Jupiter to the magnetosphere, which is suggested to be the dominant driver of Jupiter’s magnetosphere (Hill, 2001; Hill et al., 1974; Vasyliunas, 1983). In addition to these global processes, the current sheet also provides a site for many localized energy conversion and transfer processes, such as reconnection (e.g., Russell et al., 1998; Sarkango et al., 2021; Vogt et al., 2020), wave‐particle interaction (e.g., Horne et al., 2008; Saur et al., 2018), and turbulence dissipation (e.g., Saur et al., 2002).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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...

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Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…In addition to the mass cycle, the current sheet also mediates the angular momentum and energy transfer from Jupiter to the magnetosphere, which is suggested to be the dominant driver of Jupiter's magnetosphere (Hill, 2001;Hill et al, 1974;Vasyliunas, 1983). In addition to these global processes, the current sheet also provides a site for many localized energy conversion and transfer processes, such as reconnection (e.g., Russell et al, 1998;Sarkango et al, 2021;Vogt et al, 2020), wave-particle interaction (e.g., Horne et al, 2008;Saur et al, 2018), and turbulence dissipation (e.g., Saur et al, 2002).…”

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confidence: 99%

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

Liu¹,

Zong²,

Blanc³

2024

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<p>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 an occurring place 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, with four-year Juno data recorded in the 20-100 Jupiter radii, post-midnight magnetosphere. The results suggest a thin current sheet whose thickness is comparable with the gyro-radius of dominant ions. Magnetic fields in the current sheet decrease in power-law with increasing radial distances. At fixed energy, the flux of electrons and protons increases with decreasing radial distances. On the other hand, at fixed radial distances, the flux decreases in power-law with increasing energy. The flux also varies with the distances to the current sheet center. The corresponding relationship can be well described by Gaussian functions peaking at the current sheet center. In addition, the statistics show the flux of oxygen- and sulfur-group ions is comparable with the flux of protons at the same energy and radial distances, indicating the non-negligible effects of heavy ions on current sheet dynamics. From these results, a statistical model of Jupiter's current sheet is constructed, which provides us with a start point of understanding the dynamics of the whole Jupiter's magnetosphere.</p>

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“…Our observations extended previous work on magnetic reconnection in the Jovian magnetosphere, as most plasmoids observed previously by Galileo or Juno were found to have large diameters, corresponding to in situ signatures lasting several minutes or longer. In contrast, the two events discussed in Sarkango et al (2021) had durations of 22 and 62 s, respectively. Under the assumption that these plasmoids traveled at the Alfven speed corresponding to that in the lobes, we had calculated their diameters to be ∼11,000 and ∼30,000 km, respectively.…”

Section: Table 1 Cursory Estimates Of Jovian Plasmoid Dimensions and ...mentioning

confidence: 91%

“…In a previous work, we reported on two Juno-based observations of flux-ropes in the Jovian magnetotail with diameters comparable to or less than the local ion-inertial length (Sarkango et al, 2021). This was made possible by the higher resolution magnetometer instrument aboard Juno as well as the presence of heavy ions in the magnetosphere, which increased plasma length scales.…”

Section: Table 1 Cursory Estimates Of Jovian Plasmoid Dimensions and ...mentioning

confidence: 99%

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

et al. 2022

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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.

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Juno Observations of Ion‐Inertial Scale Flux Ropes in the Jovian Magnetotail

Cited by 7 publications

References 55 publications

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

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

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

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