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104 results on '"F. Bagenal"'

1. Ion Precipitation Into Io's Poles Driven by a Strong Sub‐Alfvénic Interaction

Author

J. R. Szalay, J. Saur, F. Allegrini, R. W. Ebert, P. W. Valek, G. Clark, K. Accetta, F. Bagenal, S. J. Bolton, P. Damiano, V. Dols, B. Mauk, D. J. McComas, C. Paranicas, Y. Sarkango, D. Strobel, A. H. Sulaiman, and R. J. Wilson

Subjects
Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Juno performed two close flybys of Io and found enhanced field‐aligned proton fluxes are absorbed by Io. These protons are absorbed at mass input rates comparable to previous estimates for hydrogen losses from Io, hence Jupiter is likely the source of hydrogen at Io. The conditions necessary for this to occur are: (a) formation of Alfvén waves at Io, (b) wave‐particle coupling to energize protons, (c) anti‐planetward transport of ions due to the magnetic mirror force and/or parallel acceleration, and (d) strong sub‐Alfvénic interaction slowing the flow connected to Io's fluxtube allowing for sufficient travel time for energized ions to transit to Io. The derived slowdown of ≤12% the upstream value is linked to filamentation within the Alfvén wing. This mechanism is likely operating at all strongly interacting satellites and provides an avenue to transfer material from a planetary body to its satellites, including exoplanets and brown dwarfs.

Published
2024
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2. Electron Beams at Europa

Author

F. Allegrini, J. Saur, J. R. Szalay, R. W. Ebert, W. S. Kurth, S. Cervantes, H. T. Smith, F. Bagenal, S. J. Bolton, G. Clark, J. E. P. Connerney, P. Louarn, B. Mauk, D. J. McComas, A. Pontoni, Y. Sarkango, P. Valek, and R. J. Wilson

Subjects
Europa, Jupiter's magnetosphere, electron, plasma, Juno, flyby, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Jupiter's moon Europa contains a subsurface ocean whose presence is inferred from magnetic field measurements, the interpretation of which depends on knowledge of Europa's local plasma environment. A recent Juno spacecraft flyby returned new observations of plasma electrons with unprecedented resolution. Specifically, powerful magnetic field‐aligned electron beams were discovered near Europa. These beams, with energies from ∼30 to ∼300 eV, locally enhance electron‐impact‐excited emissions and ionization in Europa's atmosphere by more than a factor three over the local space environment, and are associated with large jumps of the magnetic fields. The beams therefore play an essential role in shaping Europa's plasma and magnetic field environment and thus need to be accounted for electromagnetic sounding of Europa's ocean and plume detection by future missions such as JUICE and Europa Clipper.

Published
2024
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3. Signatures of Open Magnetic Flux in Jupiter's Dawnside Magnetotail

Author

P. A. Delamere, R. J. Wilson, S. Wing, A. R. Smith, B. Mino, C. Spitler, P. Damiano, K. Sorathia, A. Sciola, J. Caggiano, J. R. Johnson, X. Ma, F. Bagenal, B. Zhang, F. Allegrini, R. Ebert, G. Clark, and O. Brambles

Subjects
open flux, Jupiter, magnetosphere, dynamics, composition, Geology, QE1-996.5, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Jupiter's magnetosphere exhibits notable distinctions from the terrestrial magnetosphere. The structure and dynamics of Jupiter's dawnside magnetosphere can be characterized as a competition between internally driven sunward flow and solar wind‐driven tailward flow. During the prime mission, Juno acquired extensive data from dawn to midnight, sampling the magnetodisc and higher latitude regions. Numerical moments from the Jovian Auroral Distributions Experiment (JADE‐I) plasma (ion) instrument revealed a mid‐latitude region of anticorotational (−vϕ) flow. While the magnitude of the flow is subject to uncertainty due to low count rates in these rarefied regions, we demonstrate in the raw JADE‐I data that the sign of vϕ is a robust measurement. Global Grid Agnostic Magnetohydrodyamics for Extended Research Applications simulations show a similar region of strongly reduced flow in proximity to open field lines. Additionally, we use Jupiter Energetic‐particle Detector Instrument integral moments to determine the Hen+/H+ ratio (where n refers to He+ or He++) and show that a transition to solar wind‐like composition occurs in the same region as the anticorotational flow. We conclude that the global simulations are consistent with the Juno data, where the simulations show a crescent of open magnetic flux that is bounded by the magnetodisc and a closed high‐latitude polar region (nominally the polar cap), which is never observed in the terrestrial magnetosphere. The distinct distribution of open flux in Jupiter's dawnside magnetosphere suggests the significance of planetary rotation and may represent a characteristic feature of rotating giant magnetospheres for future exploration.

Published
2024
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4. Europa Modifies Jupiter's Plasma Sheet

Author

J. R. Szalay, J. Saur, D. J. McComas, F. Allegrini, F. Bagenal, S. J. Bolton, R. W. Ebert, T. K. Kim, G. Livadiotis, A. R. Poppe, P. Valek, R. J. Wilson, and E. J. Zirnstein

Subjects
Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Jupiter's plasma sheet has been understood to be primarily composed of Io‐genic sulfur and oxygen, along with protons at lower mass density. These ions move radially away from Jupiter, filling its magnetosphere. The material in the plasma sheet interacts with Europa, which is also a source of magnetospheric pickup ions, primarily hydrogen and oxygen. Juno's thermal plasma instrument JADE, the Jovian Auroral Distributions Experiment, has provided comprehensive in situ observations of the composition of Jupiter's plasma sheet ions with its Time‐of‐Flight mass‐spectrometry capabilities. Here, we present observations of the magnetospheric composition in the Europa‐Ganymede region of Jupiter's magnetosphere. We find material from Europa is intermittently present at comparable densities to Io‐genic plasma. The intermittency of Europa‐genic signatures suggests Europa's neutral oxygen toroidal cloud is more localized to Europa's vicinity than its hydrogen cloud. These observations reveal a more complex and compositionally diverse magnetosphere than previously thought.

Published
2024
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5. Jovian Magnetospheric Injections Observed by the Hubble Space Telescope and Juno

Author

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

Subjects
Jupiter, aurora, magnetosphere, injections, plasma, dynamics, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract 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.

Published
2023
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6. Investigating the Occurrence of Kelvin‐Helmholtz Instabilities at Jupiter's Dawn Magnetopause

Author

J. Montgomery, R. W. Ebert, F. Allegrini, F. Bagenal, S. J. Bolton, G. A. DiBraccio, S. A. Fuselier, R. J. Wilson, and Adam Masters

Subjects
Jupiter, Kelvin‐Helmholtz, magnetosphere, magnetopause, KHI, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract We use the Kelvin‐Helmholtz instability (KHI) condition with particle and magnetic field observations from Jovian Auroral Distributions Experiment and MAG on Juno along the dawn flank of Jupiter's magnetosphere. We identify the occurrence of magnetopause crossings that show evidence of being KH (Kelvin‐Helmholtz) unstable. When estimating the k vector to be parallel to the velocity shear, we find that 25 of 62 (40%) magnetopause crossings satisfy the KHI condition. When considering the k vector of the maximum growth rate through a solid angle approach, we find that 60 of 62 (97%) events are KH unstable. This study shows evidence of KH waves at Jupiter's dawn flank, including primary drivers such as high velocity shears and changes in plasma pressure. Signatures of magnetic reconnection were also observed in ∼25% of the KH unstable crossings. We discuss these results and their implication for the prevalence of KHI at Juno's dawn magnetopause as measured by Juno.

Published
2023
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7. Poynting Fluxes, Field‐Aligned Current Densities, and the Efficiency of the Io‐Jupiter Electrodynamic Interaction

Author

A. H. Sulaiman, J. R. Szalay, G. Clark, F. Allegrini, F. Bagenal, M. J. Brennan, J. E. P. Connerney, V. Hue, W. S. Kurth, R. L. Lysak, J. D. Nichols, J. Saur, and S. J. Bolton

Subjects
Jupiter, Io, magnetosphere, aurora, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Juno's highly inclined orbits provide opportunities to sample high‐latitude magnetic field lines connected to the orbit of Io, among the other Galilean satellites. Its payload offers both remote‐sensing and in‐situ measurements of the Io‐Jupiter interaction. These are at discrete points along Io's footprint tail and at least one event (12th perijove) was confirmed to be on a flux tube Alfvénically connected to Io, allowing for an investigation of how the interaction evolves down‐tail. Here we present Alfvén Poynting fluxes and field‐aligned current densities along field lines connected to Io and its orbit. We explore their dependence as a function of down‐tail distance and show the expected decay as seen in UV brightness and electron energy fluxes. We show that the Alfvén Poynting and electron energy fluxes are highly correlated and related by an efficiency that is fully consistent with acceleration from Alfvén wave filamentation via a turbulent cascade process.

Published
2023
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8. Jovian High‐Latitude Ionospheric Ions: Juno In Situ Observations

Author

P. W. Valek, F. Allegrini, F. Bagenal, S. J. Bolton, J. E. P. Connerney, R. W. Ebert, T. K. Kim, S. M. Levin, P. Louarn, D. J. Mccomas, J. R. Szalay, M. F. Thomsen, and R. J. Wilson

Subjects
Jupiter, ionosphere, high latitude, ions, in situ, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract The low‐altitude, high‐velocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the first in situ observations of the high‐latitude ionospheric plasma. Ions are observed to energies below 1 eV. The high‐latitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, suggesting precipitating magnetospheric ions contribute to the heating of the upper ionosphere, raising the scale height, and pushing ionospheric ions to altitudes of 0.5 RJ above the planet where they are observed by Jovian Auroral Distributions Experiment. The source of the magnetospheric ions is tied to the Io torus and plasma sheet, indicated by the cutoff seen in both the magnetospheric and ionospheric plasma at the Io M‐shells. Equatorward of the Io M‐shell boundary, the ionospheric ions are not observed, indicating a drop in the scale height of the ionospheric ions at those latitudes.

Published
2019
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12. Simultaneous UV Images and High-Latitude Particle and Field Measurements During an Auroral Dawn Storm at Jupiter

Author

R. W. Ebert, T. K. Greathouse, G. Clark, V. Hue, F. Allegrini, F. Bagenal, S. J. Bolton, B. Bonfond, J. E P Connerney, G. R. Gladstone, M. Imai, S. Kotsiaros, W. S. Kurth, S. Levin, P. Louarn, B. H. Mauk, D. J. Mccomas, C. Paranicas, A. H. Sulaiman, J. R. Szalay, M. F. Thomsen, and R. J. Wilson

Subjects
Astrophysics
Abstract

We present multi-instrument Juno observations on day-of-year 86, 2017 that link particles and fields in Jupiter's polar magnetosphere to transient UV emissions in Jupiter's northern auroral region known as dawn storms. Juno ranged from 42°N to 51°N in magnetic latitude and 5.8–7.8 Jovian radii (1 RJ = 71,492 km) during this period. These dawn storm emissions consisted of two separate, elongated structures which extended into the nightside, rotated with the planet, had enhanced brightness (up to at least 1.4 megaRayleigh) and high color ratios. The color ratio is a proxy for the atmospheric penetration depth and therefore the energy of the electrons that produce the UV emissions. Juno observed electrons and ions on magnetic field lines mapping to these emissions. The electrons were primarily field-aligned, bidirectional, and, at times, exhibited sudden intensity decreases below ∼10 keV coincident with intensity enhancements up to energies of ∼1,000 keV, consistent with the high color ratio observations. The more energetic electron distributions had characteristic energies of ∼160–280 keV and downward energy fluxes (∼70–135 mW m−2) that were a significant fraction needed to produce the UV emissions for this event. Magnetic field perturbations up to ∼0.7% of the local magnetic field showing evidence of upward and downward field-aligned currents, whistler mode waves, and broadband kilometric radio emissions were also observed along Juno's trajectory during this time frame. These high-latitude observations show similarities to those in the equatorial magnetosphere associated with dynamics processes such as interchange events, plasma injections, and/or tail reconnection.

Published
2021
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16. Pluto's Interaction With Energetic Heliospheric Ions

Author

P. Kollmann, M. E. Hill, R. C. Allen, R. L. McNutt, L. E. Brown, N. P. Barnes, P. Delamere, G. Clark, G. B. Andrews, N. Salazar, J. Westlake, G. Romeo, J. Vandegriff, M. Kusterer, D. Smith, K. Nelson, S. Jaskulek, R. B. Decker, A. F. Cheng, S. M. Krimigis, C. M. Lisse, D. G. Mitchell, H. A. Weaver, H. A. Elliott, E. Fattig, G. R. Gladstone, P. W. Valek, S. Weidner, J. Kammer, F. Bagenal, M. Horanyi, D. Kaufmann, A. Harch, C. B. Olkin, M. R. Piquette, J. R. Spencer, L. A. Young, K. Ennico, M. E. Summers, and S. A. Stern

Published
2019
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23. In Situ Observations Connected to the Io Footprint Tail Aurora

Author

J. R. Szalay, B. Bonfond, F. Allegrini, F. Bagenal, S. Bolton, G. Clark, J. E. P. Connerney, R. W. Ebert, R. E. Ergun, G. R. Gladstone, D. Grodent, G. B. Hospodarsky, V. Hue, W. S. Kurth, S. Kotsiaros, S. M. Levin, P. Louarn, B. Mauk, D. J. McComas, J. Saur, P. W. Valek, and R. J. Wilson

Published
2018
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25. How Bi‐Modal Are Jupiter's Main Aurora Zones?

Author

B. H. Mauk, J. R. Szalay, F. Allegrini, F. Bagenal, S. J. Bolton, G. Clark, J. E. P. Connerney, G. R. Gladstone, D. K. Haggerty, P. Kollmann, W. S. Kurth, C. P. Paranicas, and A. H. Sulaiman

Subjects
Geophysics, Space and Planetary Science
Published
2023

28. Juno‐UVS approach observations of Jupiter's auroras

Author

G. R. Gladstone, M. H. Versteeg, T. K. Greathouse, V. Hue, M. W. Davis, J.‐C. Gérard, D. C. Grodent, B. Bonfond, J. D. Nichols, R. J. Wilson, G. B. Hospodarsky, S. J. Bolton, S. M. Levin, J. E. P. Connerney, A. Adriani, W. S. Kurth, B. H. Mauk, P. Valek, D. J. McComas, G. S. Orton, and F. Bagenal

Published
2017
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30. A new view of Jupiter's auroral radio spectrum

Author

W. S. Kurth, M. Imai, G. B. Hospodarsky, D. A. Gurnett, P. Louarn, P. Valek, F. Allegrini, J. E. P. Connerney, B. H. Mauk, S. J. Bolton, S. M. Levin, A. Adriani, F. Bagenal, G. R. Gladstone, D. J. McComas, and P. Zarka

Published
2017
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36. Initial Results from the New Horizons Exploration of 2014 MU69, a Small Kuiper Belt Object

Author

S. A. Stern, H. A. Weaver, J. R. Spencer, C. B. Olkin, G. R. Gladstone, W. M. Grundy, J. M. Moore, D. P. Cruikshank, H. A. Elliott, W. B. McKinnon, J. Wm. Parker, A. J. Verbiscer, L. A. Young, D. A. Aguilar, J. M. Albers, T. Andert, J. P. Andrews, F. Bagenal, M. E. Banks, B. A. Bauer, J. A. Bauman, K. E. Bechtold, C. B. Beddingfield, N. Behrooz, K. B. Beisser, S. D. Benecchi, E. Bernardoni, R. A. Beyer, S. Bhaskaran, C. J. Bierson, R. P. Binzel, E. M. Birath, M. K. Bird, D. R. Boone, A. F. Bowman, V. J. Bray, D. T. Britt, L. E. Brown, M. R. Buckley, M. W. Buie, B. J. Buratti, L. M. Burke, S. S. Bushman, B. Carcich, A. L. Chaikin, C. L. Chavez, A. F. Cheng, E. J. Colwell, S. J. Conard, M. P. Conner, C. A. Conrad, J. C. Cook, S. B. Cooper, O. S. Custodio, C. M. Dalle Ore, C. C. DeBoy, P. Dharmavaram, R. D. Dhingra, G. F. Dunn, A. M. Earle, A. F. Egan, J. Eisig, M. R. El-Maarry, C. Engelbrecht, B. L. Enke, C. J. Ercol, E. D. Fattig, C. L. Ferrell, T. J. Finley, J. Firer, J. Fischetti, W. M. Folkner, M. N. Fosbury, G. H. Fountain, J. M. Freeze, L. Gabasova, L. S. Glaze, J. L. Green, G. A. Griffith, Y. Guo, M. Hahn, D. W. Hals, D. P. Hamilton, S. A. Hamilton, J. J. Hanley, A. Harch, K. A. Harmon, H. M. Hart, J. Hayes, C. B. Hersman, M. E. Hill, T. A. Hill, J. D. Hofgartner, M. E. Holdridge, M. Horanyi, A. Hosadurga, A. D. Howard, C. J. A. Howett, S. E. Jaskulek, D. E. Jennings, J. R. Jensen, M. R. Jones, H. K. Kang, D. J. Katz, D. E. Kaufmann, J. J. Kavelaars, J. T. Keane, G. P. Keleher, M. Kinczyk, M. C. Kochte, P. Kollmann, S. M. Krimigis, G. L. Kruizinga, D. Y. Kusnierkiewicz, M. S. Lahr, T. R. Lauer, G. B. Lawrence, J. E Lee, E. J. Lessac-Chenen, I. R. Linscott, C. M. Lisse, A. W. Lunsford, D. M. Mages, V. A. Mallder, N. P. Martin, B. H. May, D. J. McComas, R. L. McNutt, Jr, D. S. Mehoke, T. S. Mehoke, D. S. Nelson, H. D. Nguyen, J. I. Nunez, A. C. Ocampo, W. M. Owen, G. K. Oxton, A. H. Parker, M. Paetzold, J. Y. Pelgrift, F. J. Pelletier, J. P. Pineau, M. R. Piquette, S. B. Porter, S. Protopapa, E. Quirico, J. A. Redfern, A. L. Regiec, H. J. Reitsema, D. C. Reuter, D. C. Richardson, J. E. Riedel, M. A. Ritterbush, S. J. Robbins, D. J. Rodgers, G. D. Rogers, D. M. Rose, P. E. Rosendall, K. D. Runyon, M. G. Ryschkewitsch, M. M. Saina, M. J. Salinas, P. M. Schenk, J. R. Scherrer, W. R. Schlei, B. Schmitt, D. J. Schultz, D. C. Schurr, F. Scipioni, R. L. Sepan, R. G. Shelton, M. R. Showalter, M. Simon, K. N. Singer, E. W. Stahlheber, D. R. Stanbridge, J. A. Stansberry, A. J. Steffl, D. F. Strobel, M. M. Stothoff, T. Stryk, J. R. Stuart, M. E. Summers, M. B. Tapley, A. Taylor, H. W. Taylor, R. M. Tedford, H. B. Throop, L. S. Turner, O. M. Umurhan, J. Van Eck, D. Velez, M. H. Versteeg, M. A. Vincent, R. W. Webbert, S. E. Weidner, G. E. Weigle, II, J. R. Wendel, O. L. White, K. E. Whittenburg, B. G. Williams, K. E. Williams, S. P. Williams, H. L. Winters, A. M. Zangari, and T. H. Zurbuchen

Subjects
Astrophysics
Abstract

The Kuiper Belt is a broad, torus-shaped region in the outer Solar System beyond Neptune’s orbit. It contains primordial planetary building blocks and dwarf planets. NASA’s New Horizons spacecraft conducted a flyby of Pluto and its system of moons on 14 July 2015. New Horizons then continued farther into the Kuiper Belt, adjusting its trajectory to fly close to the small Kuiper Belt object (486958) 2014 MU69 (henceforth MU69; also informally known as Ultima Thule). Stellar occultation observations in 2017 showed that MU69 was ~25 to 35 km in diameter, and therefore smaller than the diameter of Pluto (2375 km) by a factor of ~100 and less massive than Pluto by a factor of ~106. MU69 is located about 1.6 billion kilometers farther from the Sun than Pluto was at the time of the New Horizons flyby. MU69’s orbit indicates that it is a “cold classical” Kuiper Belt object, thought to be the least dynamically evolved population in the Solar System. A major goal of flying past this target is to investigate accretion processes in the outer Solar System and how those processes led to the formation of the planets. Because no small Kuiper Belt object had previously been explored by spacecraft, we also sought to provide a close-up look at such a body’s geology and composition, and to search for satellites, rings, and evidence of present or past atmosphere. We report initial scientific results and interpretations from that flyby.

Published
2019
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38. Juno's Close Encounter With Ganymede—An Overview

Author

C. J. Hansen, S. Bolton, A. H. Sulaiman, S. Duling, F. Bagenal, M. Brennan, J. Connerney, G. Clark, J. Lunine, S. Levin, W. Kurth, A. Mura, C. Paranicas, F. Tosi, and P. Withers

Subjects
Geophysics, General Earth and Planetary Sciences
Published
2022

40. Energetic Charged Particle Fluxes Relevant to Ganymede's Polar Region

Author

C. Paranicas, B. H. Mauk, P. Kollmann, G. Clark, D. K. Haggerty, J. Westlake, L. Liuzzo, A. Masters, T. A. Cassidy, F. Bagenal, and S. Bolton

Subjects
Geophysics, Physics::Space Physics, General Earth and Planetary Sciences
Abstract

The JEDI instrument made measurements of energetic charged particles near Ganymede during a close encounter with that moon. Here we find ion flux levels are similar close to Ganymede itself but outside its magnetosphere and on near wake and open field lines. But energetic electron flux levels are more than a factor of 2 lower on polar and near-wake field lines than on nearby Jovian field lines at all energies reported here. Flux levels are relevant to the weathering of the surface, particularly processes that affect the distribution of ice, since surface brightness has been linked to the open-closed field line boundary. For this reason, we estimate the sputtering rates expected in the polar regions due to energetic heavy ions. Other rates, such as those related to radiolysis by plasma and particles that can reach the surface, need to be added to complete the picture of charged particle weathering.

Published
2022

41. Energetic Charged Particle Observations During Juno's Close Flyby of Ganymede

Author

G. Clark, P. Kollmann, B. H. Mauk, C. Paranicas, D. Haggerty, A. Rymer, H. T. Smith, J. Saur, F. Allegrini, S. Duling, R. W. Ebert, W. S. Kurth, R. Gladstone, T. K. Greathouse, W. Li, F. Bagenal, J. E. P. Connerney, S. Bolton, J. R. Szalay, A. H. Sulaiman, C. J. Hansen, and D. L. Turner

Subjects
Geophysics, General Earth and Planetary Sciences
Published
2022

42. Influence of Solar Disturbances on Galactic Cosmic Rays in the Solar Wind, Heliosheath, and Local Interstellar Medium: Advanced Composition Explorer, New Horizons, and Voyager Observations

Author

M. E. Hill, R. C. Allen, P. Kollmann, L. E. Brown, R. B. Decker, R. L. McNutt, S. M. Krimigis, G. B. Andrews, F. Bagenal, G. Clark, H. A. Elliott, S. E. Jaskulek, M. B. Kusterer, R. A. Leske, C. M. Lisse, R. A. Mewaldt, K. S. Nelson, J. D. Richardson, G. Romeo, N. A. Salazar, J. D. Vandegriff, E. A. Bernardoni, G. R. Gladstone, M. Horanyi, I. R. Linscott, K. N. Singer, A. J. Steffl, M. E. Summers, H. B. Throop, L. A. Young, C. B. Olkin, J. Wm. Parker, J. R. Spencer, S. A. Stern, A. J. Verbiscer, and H. A. Weaver

Published
2020
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45. Evidence of Alfvénic Activity in Jupiter's Mid‐To‐High Latitude Magnetosphere

Author

C. T. S. Lorch, L. C. Ray, R. J. Wilson, F. Bagenal, F. Crary, P. A. Delamere, P. A. Damiano, C. E. J. Watt, and F. Allegrini

Subjects
Geophysics, Space and Planetary Science, F500
Abstract

Using a combination of Juno magnetometer and plasma data, we show evidence of Alfvénic turbulence within the mid‐to‐high latitude magnetosphere with sufficient conditions to trigger auroral particle acceleration. We analyze 12 events that, in agreement with theoretical results, are found to be dissipative at the electron inertial scale. Furthermore, these events contain significant Poynting flux in the range ∼0.8–20 mW/m2 at ionospheric altitudes. This is sufficient to generate auroral emissions. We confirm that such events are incompressible, confirming their Alfvénicity, occur at dissipative scales, have intermittent features present and are multifractal in nature. These results illustrate the importance of turbulence in the mid‐to‐high latitudes of Jupiter's magnetosphere as a driver of particle acceleration.

Published
2022

47. Loss of Energetic Ions Comprising the Ring Current Populations of Jupiter's Middle and Inner Magnetosphere

Author

B. H. Mauk, F. Allegrini, F. Bagenal, S. J. Bolton, G. Clark, J. E. P. Connerney, D. J. Gershman, D. K. Haggerty, V. Hue, M. Imai, P. Kollmann, W. S. Kurth, Q. Nénon, C. P. Paranicas, A. M. Rymer, H. T. Smith, A. H. Sulaiman, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Geophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Jupiter, ring current, magnetosphere, energetic particles, precipitation, losses
Abstract

International audience; The low-altitude, polar orbit of the Juno mission allows the Jupiter Energetic Particle Detector Instrument to view into, and resolve, the loss cone of energetic ions comprising the low-altitude extension of Jupiter's ring current ions. For regions mapping from just inside Ganymede's orbit to well beyond Ganymede's orbit, energetic ions (>50 keV H+ and >130 keV Oxygen and Sulfur ions) are strongly scattered into the loss cone and lost to the magnetosphere at the "strong diffusion limit" at essentially all times. We conclude, by arguing against magnetic curvature scattering, that the cause is waves, perhaps associated with Alfvénic variations previously documented in this equatorial region. Scattering is generally weak or nonexistent near the orbits of the moons Europa and Io, except for the regions just downstream of the corotating plasmas. For Io, we sometimes observe moderate, but not saturated, scattering within roughly 60° downstream. Significantly, scattering is weak or nonexistent just upstream of Io's position, an asymmetry echoed in some previous wave observations. A preliminary accounting of the total (longitude-averaged) scattering losses near Io's orbit yields loss rates of order 4%-5% of the strong diffusion limit for H+ and 5%-7% for heavy ions (O + S). We conclude that near Io's orbit, charge exchange losses likely dominate over scattering losses for heavy ions and for the lower energy H+ ions (roughly

Published
2022

48. Suprathermal Ions in the Outer Heliosphere

Author

Peter Kollmann, M. E. Hill, R. L. McNutt, L. E. Brown, R. C. Allen, G. Clark, B. Andrews, N. Salazar, J. Westlake, G. Romeo, J. Vandegriff, M. Kusterer, D. Smith, S. Jaskulek, R. Decker, A. F. Cheng, S. M. Krimigis, C. M. Lisse, D. G. Mitchell, H. A. Weaver, P. Delamere, H. A. Elliott, E. Fattig, G. R. Gladstone, P. W. Valek, S. Weidner, F. Bagenal, M. Horányi, J. A. Kammer, D. Kaufmann, C. B. Olkin, M. R. Piquette, J. R. Spencer, A. J. Steffl, S. A. Stern, L. A. Young, K. Ennico, I. R. Linscott, D. F. Strobel, M. E. Summers, and J. R. Szalay

Published
2019
Full Text
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50. Magnetospheric Studies: A requirement for addressing interdisciplinary mysteries in the Ice Giant systems

Author

Peter Kollmann, F. Allegini, R. C. Allen, N. André, A. R. Azari, F. Bagenal, C. B. Beddingfield, D. Brain, P. Brandt, X. Cao, R. J. Cartwright, G. Clark, I. Cohen, J. F. Cooper, F. Crary, E. J. Leonard, C. Paty, I. de Pater, R. T. Desai, G. A. DiBraccio, W. Dietrich, C. Dong, R. W. Ebert, M. Felici, R. J. Filwett, G. Fischer, D. J. Gershman, M. Gkioulidou, T. K. Greathouse, L. Griton, M. Gritsevich, K. Hibbitts, G. Hospodarsky, V. Hue, G. Hunt, H. L. F. Huybrighs, M. Imai, C. M. Jackman, J. M. Jasinski, X. Jia, I. Jun, A. Kotova, W. S. Kurth, L. Lamy, J. Lazio, S. Lejosne, C. Louis, A. Masters, B. Mauk, H. Madanian, K. E. Mandt, R. McNutt, Jr., H. Melin, S. Miller, L. Moore, Q. Nenon, F. M. Neubauer, T. Nordheim, B. Palmaerts, C. Paranicas, P. Phipps, L. Regoli, K. Retherford, L. Roth, E. Roussos, K. D. Runyon, A. Rymer, J. Saur, D. Santos-Costa, Y. Y. Shprits, L. J. Spilker, T. Stallard, A. G. Smirnov, K. Soderlund, S. Stanley, A. H. Sulaiman, J. R. Szalay, D. L. Turner, S. Vines, L. Wang, B. Weiss, J. Wicht, R. J. Wilson, and E. Woodfield

Subjects
010504 meteorology & atmospheric sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, Geology, Ice giant, 0105 earth and related environmental sciences, Astrobiology
Published
2021

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