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1. Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby

Author

Duling, Stefan, Saur, Joachim, Clark, George, Allegrini, Frederic, Greathouse, Thomas, Gladstone, Randy, Kurth, William, Connerney, John E. P., Bagenal, Fran, and Sulaiman, Ali H.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Space Physics
Abstract

On June 7th, 2021 the Juno spacecraft visited Ganymede and provided the first in situ observations since Galileo's last flyby in 2000. The measurements obtained along a one-dimensional trajectory can be brought into global context with the help of three-dimensional magnetospheric models. Here we apply the magnetohydrodynamic model of Duling et al. (2014) to conditions during the Juno flyby. In addition to the global distribution of plasma variables we provide mapping of Juno's position along magnetic field lines, Juno's distance from closed field lines and detailed information about the magnetic field's topology. We find that Juno did not enter the closed field line region and that the boundary between open and closed field lines on the surface matches the poleward edges of the observed auroral ovals. To estimate the sensitivity of the model results, we carry out a parameter study with different upstream plasma conditions and other model parameters.

Published
2022
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2. Alternating north-south brightness ratio of Ganymede's auroral ovals: Hubble Space Telescope observations around the Juno PJ34 flyby

Author

Saur, Joachim, Duling, Stefan, Wennmacher, Alexandre, Willmes, Clarissa, Roth, Lorenz, Strobel, Darrell F., Allegrini, Frédéric, Bagenal, Fran, Bolton, Scott J., Bonfond, Bertrand, Clark, George, Gladstone, Randy, Greathouse, T. K., Grodent, Denis C., Hansen, Candice J., Kurth, W. S., Orton, Glenn S., Retherford, Kurt D., Rymer, Abigail M., and Sulaiman, Ali H.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Space Physics
Abstract

We report results of Hubble Space Telescope observations from Ganymede's orbitally trailing side which were taken around the flyby of the Juno spacecraft on June 7, 2021. We find that Ganymede's northern and southern auroral ovals alternate in brightness such that the oval facing Jupiter's magnetospheric plasma sheet is brighter than the other one. This suggests that the generator that powers Ganymede's aurora is the momentum of the Jovian plasma sheet north and south of Ganymede's magnetosphere. Magnetic coupling of Ganymede to the plasma sheet above and below the moon causes asymmetric magnetic stresses and electromagnetic energy fluxes ultimately powering the auroral acceleration process. No clear statistically significant time variability of the auroral emission on short time scales of 100s could be resolved. We show that electron energy fluxes of several tens of mW m$^{-2}$ are required for its OI 1356 \AA$\;$ emission making Ganymede a very poor auroral emitter., Comment: Accepted for publication with Geophys. Res. Let

Published
2022
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3. Anisotropic kappa distributions I: Formulation based on particle correlations

Author

Livadiotis, George, Nicolaou, George, and Allegrini, Frederic

Subjects
Condensed Matter - Statistical Mechanics, Physics - Plasma Physics, Physics - Space Physics
Abstract

We develop the theoretical basis for the connection of the variety of anisotropic distributions with the statistical correlations among particles velocity components. By examining the most common anisotropic distribution, we derive the correlation coefficient among particle energies, show how this correlation is connected to the effective dimensionality of the velocity distribution, and derive the connection between anisotropy and adiabatic polytropic index. Having established the importance of correlation among particles in the formulation of anisotropic kappa distributions, we generalize these distributions within the framework of nonextensive statistical mechanics and based on the types of homogeneous or heterogeneous correlations among the particles velocity components. The formulation of the developed generalized distributions mediates the main two types of anisotropic kappa distributions, considering (a) equal correlations, or (b) zero correlations, among different velocity components. Finally, the developed anisotropic kappa distributions are expressed in terms of the energy and pitch angle in arbitrary reference frames., Comment: 46 pages, 15 figures

Published
2020
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4. Solar System Ice Giants: Exoplanets in our Backyard

Author

Rymer, Abigail, Mandt, Kathleen, Hurley, Dana, Lisse, Carey, Izenberg, Noam, Smith, H. Todd, Westlake, Joseph, Bunce, Emma, Arridge, Christopher, Masters, Adam, Hofstadter, Mark, Simon, Amy, Brandt, Pontus, Clark, George, Cohen, Ian, Allen, Robert, Vine, Sarah, Hansen, Kenneth, Hospodarsky, George, Kurth, William, Romani, Paul, Lamy, Laurent, Zarka, Philippe, Cao, Hao, Paty, Carol, Hedman, Matthew, Roussos, Elias, Cruikshank, Dale, Farrell, William, Fieseler, Paul, Coates, Andrew, Yelle, Roger, Parkinson, Christopher, Militzer, Burkhard, Grodent, Denis, Kollmann, Peter, McNutt, Ralph, André, Nicolas, Strange, Nathan, Barnes, Jason, Dones, Luke, Denk, Tilmann, Rathbun, Julie, Lunine, Jonathan, Desai, Ravi, Cochrane, Corey, Sayanagi, Kunio M., Postberg, Frank, Ebert, Robert, Hill, Thomas, Mueller-Wodarg, Ingo, Regoli, Leonardo, Pontius, Duane, Stanley, Sabine, Greathouse, Thomas, Saur, Joachim, Marouf, Essam, Bergman, Jan, Higgins, Chuck, Johnson, Robert, Thomsen, Michelle, Soderlund, Krista, Jia, Xianzhe, Wilson, Robert, Englander, Jacob, Burch, Jim, Nordheim, Tom, Grava, Cesare, Baines, Kevin, Quick, Lynnae, Russell, Christopher, Cravens, Thomas, Cecconi, Baptiste, Aslam, Shahid, Bray, Veronica, Garcia-Sage, Katherine, Richardson, John, Clark, John, Hsu, Sean, Achterberg, Richard, Sergis, Nick, Paganelli, Flora, Kempf, Sasha, Orton, Glenn, Portyankina, Ganna, Jones, Geraint, Economou, Thanasis, Livengood, Timothy, Krimigi, Stamatios, Szalay, James, Jackman, Catriona, Valek, Phillip, Lecacheux, Alain, Colwell, Joshua, Jasinski, Jamie, Tosi, Federico, Sulaiman, Ali, Galand, Marina, Kotova, Anna, Khurana, Krishan, Kivelson, Margaret, Strobel, Darrell, Radiota, Aikaterina, Estrada, Paul, Livi, Stefano, Azari, Abigail, Yates, Japheth, Allegrini, Frederic, Vogt, Marissa, Felici, Marianna, Luhmann, Janet, Filacchione, Gianrico, and Moore, Luke

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Future remote sensing of exoplanets will be enhanced by a thorough investigation of our solar system Ice Giants (Neptune-size planets). What can the configuration of the magnetic field tell us (remotely) about the interior, and what implications does that field have for the structure of the magnetosphere; energy input into the atmosphere, and surface geophysics (for example surface weathering of satellites that might harbour sub-surface oceans). How can monitoring of auroral emission help inform future remote observations of emission from exoplanets? Our Solar System provides the only laboratory in which we can perform in-situ experiments to understand exoplanet formation, dynamos, systems and magnetospheres., Comment: Exoplanet Science Strategy White Paper, submitted to the National Academies of Sciences, Engineering and Medicine, Space Studies Board, 9 March 2018

Published
2018

5. Ion Parameters Dataset From Juno/JADE Observations in Jupiter's Magnetosphere Between 10 and 50 RJ.

Author

Wang, Jian‐zhao, Bagenal, Fran, Wilson, Robert J., Valek, Philip W., Ebert, Robert W., and Allegrini, Frederic

Subjects
HEAVY ions, THERMAL plasmas, FLOW velocity, ORBITS (Astronomy), ION migration & velocity
Abstract

After its arrival at Jupiter in July 2016, Juno conducted a global survey of Jupiter's magnetosphere (especially the equatorial plasma disk region) with its highly eccentric polar orbit. Since then, the JADE instrument has accumulated a large amount of plasma measurements. Using a developed forward modeling method and the Alpine supercomputer cluster at CU Boulder, we fit all ion measurements between 10 and 50 RJ ${\mathrm{R}}_{\mathrm{J}}$ from PJ5 to PJ56, obtaining a dataset with 70,487 good fits that consists of the following set of plasma parameters: abundances of different heavy ions, density, temperature, and 3‐D bulk flow velocity of heavy ions. An overview of the dataset and an example use on flux tube interchange are presented to illustrate its effectiveness and usefulness. In the investigated interchange event that occurred at ∼ ${\sim} $14 RJ ${\mathrm{R}}_{\mathrm{J}}$, the plasma disk is variable and heated, with alternating hotter inflows and colder outflows, accompanied by small perturbations in the magnetic fields. This dataset has the potential for many applications. Key Points: A dataset from thermal plasma observations of Juno using a forward modeling methodThe dataset includes ion abundances, density, temperature, and 3‐D bulk flow velocityThe dataset consists of 70,487 data points obtained between 10 and 50 RJ from Juno orbits PJ5 to PJ56 [ABSTRACT FROM AUTHOR]

Published
2024
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6. Dawn‐Dusk Asymmetry of Plasma Flow in Jupiter's Middle Magnetosphere Observed by Juno.

Author

Wang, Jian‐Zhao, Bagenal, Fran, Wilson, Robert J., Nerney, Edward, Ebert, Robert W., Valek, Philip W., Allegrini, Frederic, Szalay, Jamey R., and Delamere, Peter A.

Subjects
LOW temperature plasmas, PLASMA flow, AURORAS, JUPITER (Planet), MAGNETIC fields
Abstract

Based on plasma observations from Juno's Joviana Auroral Distributions Experiment instrument and forward modeling, we investigate the dawn‐dusk asymmetries within Jupiter's magnetosphere between 10 and 40 RJ ${\mathrm{R}}_{J}$. On the dawnside, the flux tubes are depleted characterized by low density and near rigid‐corotation velocity, with a low temperature and thin plasma sheet. On the duskside, the flux tubes are assimilated characterized by high density and sub‐corotation velocity, with a hotter and thicker plasma sheet. Super‐corotating hot inflows originating from reconnection events are identified in the pre‐dawn sector. These observations are consistent with the Vasyliūnas cycle, suggesting it operates in a region closer to Jupiter than previous studies suggested. Outflows are locally coupled with swept‐back magnetic fields and are frequently observed near midnight. Inflows are locally coupled with swept‐forward fields with higher temperatures. The discernible temperature difference between inflows and outflows reveals their distinct origins. Plasma beta increases with radial distance, suggesting increased instabilities at larger distances. Plain Language Summary: Jupiter's magnetosphere is internally driven by plasma originating from its moons, particularly Io. As the plasma corotates around Jupiter and is transported outward, the force balance breaks with stretched magnetic field and pinched off plasma blobs, resulting in local time asymmetry. For the first time, this asymmetry is validated within 40 Jupiter radii using plasma observations from the Juno mission. Compared to the duskside, the dawnside plasma exhibits lower density, higher temperature, and larger corotational velocity (even exceeds rigid corotation sometimes). These results indicate distinct origins for inflows and outflows. This study brings us a step forward in our understanding of the dynamics of Jupiter's magnetosphere and provides a data set for comparison with simulations. Key Points: The dawn‐dusk asymmetry between 10 and 40 RJ is modulated by the Vasyliūnas cycle, featuring super‐corotating flows in the pre‐dawn sectorThe flux tubes are depleted and accelerated on the dawnside, while they are dense and sub‐corotational on the dusksideThe temperature difference between inflows and outflows suggests physically distinct origins [ABSTRACT FROM AUTHOR]

Published
2024
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8. Energetic charged particle observations of Europa’s near-space environment during the Juno PJ45 flyby and anticipations for the JUICE mission 

Author

Clark, George, primary, Mauk, Barry, additional, Paranicas, Chris, additional, Brandt, Pontus, additional, Kollmann, Peter, additional, Smith, Todd, additional, Allegrini, Frederic, additional, Bolton, Scott, additional, Mitchell, Don, additional, Gkioulidou, Matina, additional, Barabash, Stas, additional, Wurz, Peter, additional, Krupp, Norbert, additional, Roussos, Elias, additional, Huybrighs, Hans, additional, Paty, Carol, additional, Jia, Xianzhe, additional, Khurana, Krishan, additional, and Pontoni, Angele, additional

Published
2024
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9. Inter-Calibration of Solar Orbiter’s Heavy Ion Sensor and Suprathermal Ion Spectrograph

Author

Alterman, Benjamin, primary, Allen, Robert, additional, Dewey, Ryan, additional, Livi, Stefano, additional, Raines, Jim, additional, Lepri, Susan, additional, Spitzer, Sarah, additional, Bert, Chris, additional, Owen, Christopher, additional, Ho, George, additional, Galvin, Antoinette, additional, Kistler, Lynn, additional, Allegrini, Frederic, additional, Ogasawara, Keiichi, additional, Wurz, Peter, additional, Philips, Mark, additional, D'Amicis, Raffaella, additional, Mason, Glen, additional, Wimmer-Schweingruber, Robert F., additional, and Rodriquez-Pacheco, Javier, additional

Published
2024
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11. Radial and Vertical Structures of Plasma Disk in Jupiter's Middle Magnetosphere.

Author

Wang, Jian‐Zhao, Bagenal, Fran, Wilson, Robert J., Nerney, Edward, Ebert, Robert W., Valek, Philip W., and Allegrini, Frederic

Subjects
MAGNETOSPHERE, PLASMA temperature, DENSE plasmas, PLASMA sources, ACCRETION disks, ELECTRIC fields
Abstract

The Juno mission flew through the plasma disk near the equator in Jupiter's magnetosphere frequently. We identify 274 plasma disk crossings of Juno between 10 and 40 RJ from PJ5 to PJ44. Using a forward modeling method that combines the JADE‐I time‐of‐flight and SPECIES data sets, we perform a survey of ion properties in the plasma disk. Ions are heated from 1.5 to 6 keV between 15 and 30 RJ. Density and temperature are locally anti‐correlated. Assumed to be related to centrifugal instabilities, cold, dense plasma are commonly observed near midnight. Plasma corotates around Jupiter and the rigid corotation breaks down outside 15–20 RJ. The plasma bulk velocity increases from the post‐dusk sector to the pre‐dawn sector featuring injection flows in the pre‐dawn sector, which is consistent with the Vasyliunas cycle. Strong outflows (>100 km/s) are commonly observed outside 20 RJ and the average radial velocity increases with radial distance. The ion abundance changes between 10 and 18 RJ and that might indicate plasma sources and/or sinks near Europa and Ganymede. The vertical distribution of ions is controlled by the balance between centrifugal, pressure gradient, and ambipolar electric field forces. An example near the M‐shell of 13.5 shows that average plasma temperature increases by a factor of 10 from the disk center to edge, because cold ions are more confined near the equator. Lighter ions with higher charge states have more mobility along the field line and have larger scale heights. The observations are compared with multi‐species diffusive equilibrium model. Key Points: The ion properties of the plasma disk are investigated based on 274 plasma disk crossings of Juno on Jupiter's nightsideStrong outflows are observed frequently outside 25 RJ and corotational velocity increases from the post‐dusk sector to the pre‐dawn sectorColder (hotter) and heavier (lighter) ions with lower (higher) charge states are more (less) confined near the equator [ABSTRACT FROM AUTHOR]

Published
2024
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13. Forward Modeling of 3-D Ion Properties in Jupiter's Magnetosphere Using Juno/JADE-I Data.

Author

Jian-zhao Wang, Bagenal, Fran, Wilson, Robert J., Nerney, Edward, Crary, Frank, Dols, Vincent, Ebert, Rob W., Valek, Phil W., Allegrini, Frederic, Kim, Thomas K., and Szalay, Jamey R.

Subjects
MAGNETOSPHERE, JUPITER (Planet), HEAVY ions, ION migration & velocity, FLOW velocity, COHEN'S kappa coefficient (Statistics)
Abstract

The Jovian Auroral Distributions Experiment Ion sensor (JADE-I) on NASA's Juno mission provides in-situ measurements of ions from 0.1 to 46.2 keV/q inside Jupiter's magnetosphere. JADE-I is used to study the plasma with two types of datasets from the same measurement: Time-of-flight (TOF) and SPECIES. The TOF dataset provides mass-per-charge measurements with a range of 1-64 amu/q but oversamples particles over 6π steradian viewing per spacecraft spin and has little directional information. On the other hand, the SPECIES dataset can provide a good measurement of the flow direction but does not provide mass-per-charge information due to the telemetry limit. In this study, we developed a 2-step forward modeling method that combines the advantages and avoids the disadvantages of TOF and SPECIES data to derive the 3-D properties of heavy ions. Assuming that the ion velocity distribution can be described with the kappa distribution, we first perform the forward model fit of the TOF data to calculate the relative abundance of heavy ion species. Then we fix the relative abundance and perform the second forward model fit on the SPECIES data. Using this method, we obtain the densities of different heavy ions, the shared temperature and kappa value, and the 3-D flow velocity vector. Some data examples of the equatorial plasma disk before Perijove 24 are included to demonstrate the method. Plasma properties can then be mapped to explore spatial and temporal variabilities in Jupiter's magnetosphere. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Source of radio emissions induced by the Galilean moons Io, Europa and Ganymede: in situ measurements by Juno

Author

Louis, Corentin Kenelm, primary, Louarn, Philippe, additional, Collet, Brieuc, additional, Clément, Noé, additional, Saati, Sariah Al, additional, Szalay, Jamey R., additional, Hue, Vincent, additional, Lamy, Laurent, additional, Kotsiaros, Stavros, additional, Kurth, William S, additional, Jackman, Caitriona M, additional, Wang, Yuxian, additional, Blanc, Michel F., additional, Allegrini, Frederic, additional, Connerney, John E. P., additional, and Gershman, Daniel J, additional

Published
2023
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15. Juno Plasma Wave Observations at Europa

Author

Kurth, William S, primary, Wilkinson, Darrelle R., additional, Hospodarsky, George Blair, additional, Santolik, Ondrej, additional, Averkamp, Terrance F., additional, Sulaiman, Ali H., additional, Menietti, John Douglas, additional, Connerney, John E. P., additional, Allegrini, Frederic, additional, Mauk, Barry H., additional, and Bolton, Scott J, additional

Published
2023
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20. Poynting fluxes, field-aligned current densities, and the efficiency of the Io-Jupiter electrodynamic interaction

Author

Sulaiman, Ali H., primary, Szalay, Jamey R., additional, Clark, George, additional, Allegrini, Frederic, additional, Bagenal, Fran, additional, Brennan, Martin, additional, Connerney, John E. P., additional, Hue, Vincent, additional, Kurth, William S, additional, Lysak, Robert Louis, additional, Nichols, Jonathan D., additional, Saur, Joachim, additional, and Bolton, Scott J, additional

Published
2023
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21. How the Juno Ganymede Flyby Has Changed our Understanding of its Aurora and Atmosphere

Author

Waite, J. Hunter, primary, Greathouse, Thomas, additional, Carberry Mogan, Shane, additional, Ebert, Rob, additional, Connerney, Jack, additional, Kurth, William, additional, Gladstone, G. Randall, additional, Allegrini, Frederic, additional, Johnson, Robert, additional, Vorberger, Audrey, additional, Valek, Phillip, additional, Clark, George, additional, Bolton, Scott, additional, and Hansen-Koharcheck, Candice, additional

Published
2023
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23. A public domain data-based modeling of long-term variability of Jupiter’s inner electron radiation belt

Author

Santos-Costa, Daniel, primary, Oyafuso, Fabiano A., additional, Levin, Steven M., additional, Connerney, John E.P., additional, Woodfield, Emma, additional, Keebler, Timothy, additional, Velusamy, Thangasamy, additional, Han, Sooman, additional, de Pater, Imke, additional, Jun, Insoo, additional, Garrett, Henry B., additional, Wilson, Rob, additional, Ebert, Rob W., additional, Allegrini, Frederic, additional, Gladstone, Randy, additional, Kollmann, Peter, additional, Mauk, Barry, additional, Kurth, William, additional, Becker, Heidi N., additional, and Bolton, Scott J., additional

Published
2023
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24. Hubble and Juno observations of Jupiter’s auroras and magnetospheric dynamics during the Juno Extended Mission

Author

Nichols, Jonathan D., primary, Clarke, John, additional, Grodent, Denis, additional, Bonfond, Bertrand, additional, Cowley, Stanley, additional, Gladstone, Randy, additional, Bagenal, Fran, additional, Orton, Glenn, additional, Lysak, Bob, additional, Allegrini, Frederic, additional, Connerney, Jack, additional, Mauk, Barry, additional, Clark, George, additional, Wilson, Rob, additional, and Ebert, Rob, additional

Published
2023
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26. Water-group pickup ions from Europa: A window into surface ice evolution

Author

Szalay, Jamey, primary, Allegrini, Frederic, additional, Ebert, Robert, additional, Bagenal, Fran, additional, Bolton, Scott, additional, Fatemi, Shahab, additional, McComas, David, additional, Pontoni, Angele, additional, Poppe, Andrew, additional, Sarkango, Yash, additional, Saur, Joachim, additional, Smith, Todd, additional, Valek, Philip, additional, Vance, Steven, additional, Vorburger, Audrey, additional, and Wilson, Robert, additional

Published
2023
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28. Evidence for electrostatic and Alfvénic accelerations in the Europa footprint tail revealed by Juno in-situ measurements

Author

Rabia, Jonas, primary, Hue, Vincent, additional, Szalay, Jamey R., additional, André, Nicolas, additional, Nénon, Quentin, additional, Blanc, Michel, additional, Allegrini, Frederic, additional, Bolton, Scott J., additional, Connerney, Jack E.P., additional, Ebert, Robert W., additional, Greathouse, Thomas K., additional, Louarn, Philippe, additional, Mura, Alessandro, additional, Penou, Emmanuel, additional, and Sulaiman, Ali H., additional

Published
2023
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30. Ganymede MHD Model: Magnetospheric Context for Juno's PJ34 Flyby

Author

Duling, Stefan, primary, Saur, Joachim, additional, Clark, George, additional, Allegrini, Frederic, additional, Greathouse, Thomas, additional, Gladstone, Randy, additional, Kurth, William, additional, Connerney, John E. P., additional, Bagenal, Fran, additional, and Sulaiman, Ali H., additional

Published
2022
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33. Closed Fluxtubes and Proton Conics in Jupiter’s Polar Cap

Author

Szalay, Jamey, primary, Clark, George, additional, Livadiotis, George, additional, McComas, David, additional, Mitchell, Don, additional, Rankin, Jamie, additional, Sulaiman, Ali, additional, Allegrini, Frederic, additional, Bagenal, Fran, additional, Ebert, Rob, additional, Gladstone, Randy, additional, Kurth, Bill, additional, Mauk, Barry, additional, Valek, Phil, additional, Wilson, Rob, additional, and Bolton, Scott, additional

Published
2022
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34. Effect of magnetospheric disturbances on Jovian radio emissions: an in situ case study from Juno data

Author

Louis, Corentin, primary, Jackman, Caitriona, additional, O’Kane Hackett, Aoife, additional, Devon-Hurley, Elliot, additional, Kurth, William, additional, Hospodarsky, George, additional, Louarn, Philippe, additional, Allegrini, Frederic, additional, Connerney, John, additional, Weigt, Dale, additional, McEntee, Sean, additional, Fogg, Alexandra, additional, Waters, James, additional, and Bolton, Scott, additional

Published
2022
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35. Water-group pickup ions from Europa-genic neutrals orbiting Jupiter 

Author

Szalay, Jamey, primary, Smith, Todd, additional, Zirnstein, Eric, additional, McComas, David, additional, Begley, Luke, additional, Bagenal, Fran, additional, Delamere, Peter, additional, Wilson, Robert, additional, Valek, Phil, additional, Poppe, Andrew, additional, Nenon, Quentin, additional, Allegrini, Frederic, additional, Ebert, Robert, additional, and Bolton, Scott, additional

Published
2022
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39. Juno Plasma Wave Observations at Ganymede

Author

Kurth, William S, primary, Sulaiman, Ali H., additional, Hospodarsky, George Blair, additional, Menietti, John Douglas, additional, Mauk, Barry H., additional, Clark, George, additional, Allegrini, Frederic, additional, Valek, Philip, additional, Connerney, John E. P., additional, Waite, Jack Hunter, additional, Bolton, Scott J, additional, Imai, Masafumi, additional, Santolik, Ondrej, additional, Li, Wen, additional, Duling, Stefan, additional, Saur, Joachim, additional, and Louis, Corentin Kenelm, additional

Published
2022
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40. Evidence for Magnetic Reconnection at Ganymede’s Upstream Magnetopause during the PJ34 Juno Flyby

Author

Ebert, Robert W., primary, Allegrini, Frederic, additional, Angold, NIgel, additional, Bagenal, Fran, additional, Bolton, Scott J., additional, Connerney, Jack, additional, DiBraccio, Gina, additional, Fattig, Eric, additional, Fuselier, Stephen A., additional, Levin, Steve, additional, McComas, David J., additional, Montgomery, Jake, additional, Romanelli, Norberto, additional, Szalay, Jamey R., additional, Valek, Phil, additional, and Wilson, Robert J., additional

Published
2022
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41. Preferential Acceleration of Suprathermal Particles at Shocks

Author

Livi, Stefano, primary, Owen, Chris, additional, Louarn, Philippe, additional, Fedorov, Andrei, additional, Alterman, Ben, additional, Lepri, Susan, additional, Raines, Jim, additional, Galvin, Antoniette, additional, Kistler, Lynn, additional, Allegrini, Frederic, additional, Ogasawara, Keiichi, additional, Wurz, Peter, additional, Bruno, Roberto, additional, D'Amicis, Raffaella, additional, and Collier, Michael, additional

Published
2022
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42. Jupiter's low-altitude auroral zones: Fields, particles, plasma waves, and density depletions

Author

Sulaiman, Ali H., primary, Allegrini, Frederic, additional, Clark, George, additional, Gladstone, Randy, additional, Kotsiaros, Stavros, additional, Kurth, William S, additional, Mauk, Barry H., additional, Szalay, Jamey R., additional, Bagenal, Fran, additional, Bonfond, Bertrand, additional, Connerney, John E. P., additional, Ebert, Robert Wilkes, additional, Elliott, Sadie Suzanne, additional, Gershman, Daniel J, additional, Hospodarsky, George Blair, additional, Hue, Vincent, additional, Lysak, Robert L., additional, Masters, Adam, additional, Santolik, Ondrej, additional, Saur, Joachim, additional, and Bolton, Scott J, additional

Published
2022
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43. Simultaneous UV Images and High-latitude Particle and Field Measurements During an Auroral Dawn Storm at Jupiter

Author

Ebert, Robert Wilkes, primary, Greathouse, Thomas K., additional, Clark, George, additional, Allegrini, Frederic, additional, Bagenal, Fran, additional, Bolton, Scott J, additional, Bonfond, Bertrand, additional, Connerney, John E. P., additional, Gladstone, Randy, additional, Hue, Vincent, additional, Imai, Masafumi, additional, Kurth, William S, additional, Levin, Steven M., additional, Louarn, Philippe, additional, Mauk, Barry H., additional, McComas, David J., additional, Paranicas, Christopher P., additional, Sulaiman, Ali H., additional, Szalay, Jamey R., additional, Thomsen, Michelle F., additional, and Wilson, Robert J., additional

Published
2021
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45. A Preliminary Study of Magnetosphere‐Ionosphere‐Thermosphere Coupling at Jupiter: Juno Multi‐Instrument Measurements and Modeling Tools

Author

Wang, Yuxian, primary, Blanc, Michel, additional, Louis, Corentin, additional, Wang, Chi, additional, André, Nicolas, additional, Adriani, Alberto, additional, Allegrini, Frederic, additional, Blelly, Pierre‐Louis, additional, Bolton, Scott, additional, Bonfond, Bertrand, additional, Clark, George, additional, Dinelli, Bianca Maria, additional, Gérard, Jean‐Claude, additional, Gladstone, Randy, additional, Grodent, Denis, additional, Kotsiaros, Stavros, additional, Kurth, William, additional, Lamy, Laurent, additional, Louarn, Philippe, additional, Marchaudon, Aurélie, additional, Mauk, Barry, additional, Mura, Alessandro, additional, and Tao, Chihiro, additional

Published
2021
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46. A new framework to explain changes in Io's footprint tail electron fluxes in the Juno era

Author

Szalay, Jamey, primary, Allegrini, Frederic, additional, Bagenal, Fran, additional, Bolton, Scott, additional, Bonfond, Bertrand, additional, Clark, George, additional, Connerney, Jack, additional, Ebert, Robert, additional, Hue, Vincent, additional, McComas, David, additional, Saur, Joachim, additional, Sulaiman, Ali, additional, and Wilson, Robert, additional

Published
2021
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47. Revealing the source of Jupiter’s x-ray auroral flares

Author

Yao, Zhonghua, primary, Dunn, William R., additional, Woodfield, Emma E., additional, Clark, George, additional, Mauk, Barry H., additional, Ebert, Robert W., additional, Grodent, Denis, additional, Bonfond, Bertrand, additional, Pan, Dongxiao, additional, Rae, I. Jonathan, additional, Ni, Binbin, additional, Guo, Ruilong, additional, Branduardi-Raymont, Graziella, additional, Wibisono, Affelia D., additional, Rodriguez, Pedro, additional, Kotsiaros, Stavros, additional, Ness, Jan-Uwe, additional, Allegrini, Frederic, additional, Kurth, William S., additional, Gladstone, G. Randall, additional, Kraft, Ralph, additional, Sulaiman, Ali H., additional, Manners, Harry, additional, Desai, Ravindra T., additional, and Bolton, Scott J., additional

Published
2021
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48. Energetic proton acceleration associated with Io's footprint tail

Author

George Clark, Barry H. Mauk, Peter Kollmann, Szalay R. Jamey, Ali H. Sulaiman, Daniel J Gershman, Joachim Saur, Sascha Janser, Katherine Garcia-Sage, Thomas K. Greathouse, Christopher P. Paranicas, Allegrini Frederic, Bagenal Fran, Scott J Bolton, John E. P. Connerney, ebert robert, George Blair Hospodarsky, Dennis K Haggerty, Vincent Hue, Masafumi Imai, Stavros Kotsiaros, mccomas David, Abigail Mary Rymer, and Joseph Hinton Westlake

Published
2020
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49. Juno Energetic Neutral Atom (ENA) Remote Measurements of Magnetospheric Injection-Dynamics in Jupiter's Io Torus Regions

Author

Mauk, Barry H., Clark, George, Allegrini, Frederic, Bolton, Scott, Connerney, John E. P., Haggerty, Dennis, Kollmann, Peter, Mitchell, Donald G., Paranicas, Chris, and Rymer, Abigail

Subjects
Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Jupiter, Planetary Magnetospheres, Energetic Particles, Energetic Neutral Atoms, Io
Abstract

In planetary magnetospheres, singly charged energetic particles, trapped by the planet’s magnetic field, can steal electrons from cold gas atoms and become neutralized. These now Energetic Neutral Atoms (ENAs), no longer confined by the magnetic field, can travel out of the system similar to photons leaving a hot oven. ENA’s have been used to image magnetospheric processes at Earth, Jupiter, and Saturn. At Jupiter, the opportunities to image the magnetosphere have been limited and always from the perspective of the near-equatorial plane at distance >139 RJ. The polar orbiting Juno mission carries the JEDI instrument that is serendipitously sensitive to ENA’s with energies > 50 keV, provided there are no charged particles in the environment to mask their presence. Here we report on the first ENA observations of Jupiter’s magnetosphere from a non-equatorial perspective. In this brief report we concentrate on emissions seen during perijove 22 (PJ22) during very active conditions, and compare them with emissions during the inactive perijove 23 (PJ23). We observe, and discriminate between, distinct ENA signatures from the neutral gases occupying the orbit of Io (away from Io itself), the orbit of Europa (away from Europa), and from Jupiter itself. Strong ENA emissions from Io’s orbit during PJ22 are associated with energetic particle injections observed near Io’s orbit several hours earlier. Some injections occurred planetward of Io’s L-shell (magnetic position), somewhat of a surprise given that injections are thought to be driven by outward transport of plasmas generated by Io., Provided here is a PDF of the a revised version of this paper, intended for the Journal of Geophysical Research. Also included is a Zip file of ASCII numbers associated with all of the Figures of the paper. The PDF of the paper provides the road map for the data files.

Published
2020
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50. Revealing the source of Jupiter’s x-ray auroral flares

Author

Yao, Zhonghua, Dunn, William R., Woodfield, Emma E., Clark, George, Mauk, Barry H., Ebert, Robert W., Grodent, Denis, Bonfond, Bertrand, Pan, Dongxiao, Rae, I. Jonathan, Ni, Binbin, Guo, Ruilong, Branduardi-Raymont, Graziella, Wibisono, Affelia D., Rodriguez, Pedro, Kotsiaros, Stavros, Ness, Jan-Uwe, Allegrini, Frederic, Kurth, William S., Gladstone, G. Randall, Kraft, Ralph, Sulaiman, Ali H., Manners, Harry, Desai, Ravindra T., Bolton, Scott J., Yao, Zhonghua, Dunn, William R., Woodfield, Emma E., Clark, George, Mauk, Barry H., Ebert, Robert W., Grodent, Denis, Bonfond, Bertrand, Pan, Dongxiao, Rae, I. Jonathan, Ni, Binbin, Guo, Ruilong, Branduardi-Raymont, Graziella, Wibisono, Affelia D., Rodriguez, Pedro, Kotsiaros, Stavros, Ness, Jan-Uwe, Allegrini, Frederic, Kurth, William S., Gladstone, G. Randall, Kraft, Ralph, Sulaiman, Ali H., Manners, Harry, Desai, Ravindra T., and Bolton, Scott J.

Abstract

Jupiter’s rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter’s x-ray flares have remained unknown. Here, we report simultaneous in situ satellite and space-based telescope observations that reveal the processes that produce Jupiter’s x-ray flares, showing surprising similarities to terrestrial ion aurora. Planetary-scale electromagnetic waves are observed to modulate electromagnetic ion cyclotron waves, periodically causing heavy ions to precipitate and produce Jupiter’s x-ray pulses. Our findings show that ion aurorae share common mechanisms across planetary systems, despite temporal, spatial, and energetic scales varying by orders of magnitude.

Published
2021

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