Article
Geosciences, Multidisciplinary
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, S. J. Bolton
Summary: Juno's highly inclined orbits provide opportunities to study the magnetic field lines connected to the orbit of Io. Its payload allows for remote-sensing and in-situ measurements of the Io-Jupiter interaction. The study presents the analysis of Alfven Poynting fluxes and field-aligned current densities along field lines connected to Io and its orbit.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
A. Moirano, A. Mura, B. Bonfond, J. E. P. Connerney, V. Dols, D. Grodent, V. Hue, J. C. Gerard, F. Tosi, A. Migliorini, A. Adriani, F. Altieri, C. Castagnoli, A. Cicchetti, B. M. Dinelli, D. Grassi, M. L. Moriconi, R. Noschese, G. Piccioni, C. Plainaki, P. Scarica, G. Sindoni, R. Sordini, D. Turrini, F. Zambon
Summary: One of the features of Jupiter's aurora is the emission caused by the orbital motion of its moon Io. The interaction between Io and the surrounding plasma generates Alfven waves that travel along the magnetic field lines towards Jupiter's ionosphere, causing the production of the Io footprint auroral emission. By studying the position of the Io footprint using JIRAM onboard Juno, researchers can retrieve information on the variability of the Io Plasma Torus and gain insights into the density and temperature variations. The results provide evidence of non-System III variability in the plasma density and temperature, suggesting either local time asymmetry or temporal variability of the torus.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Xiaoyi Tan, Fei He, Masato Kagitani, Yong Zhao, Zhonghua Yao, Zhaojin Rong, Yong Wei
Summary: In this study, a three-dimensional model of the Io plasma torus is compiled and simulated emissions are conducted, which match well with previous observations. This work provides a convenient tool for observing and obtaining physical parameters of the plasma torus.
EARTH AND SPACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Thamis C. F. Carvalho Ferreira, Antonio F. Bertachini A. Prado, Silvia M. Giuliatti Winter, Lucas S. Ferreira
Summary: This paper studies the best initial orbital conditions for orbits around Io, taking into account the perturbative effects of Jupiter and the mass configuration of Io. Numerical simulations were conducted to investigate the initial orbital parameters of the probe. The results show that although most orbits have short lifetimes, there are regions where satisfactory times for future missions around Io can be achieved.
Article
Geochemistry & Geophysics
Isamu N. Matsuyama, Teresa Steinke, Francis Nimmo
Summary: Io, with its close distance and elliptic orbit to Jupiter, experiences strong and periodic gravitational tides that generate internal friction and heat its interior. This makes Io unique in our Solar System and provides an ideal laboratory for studying the fundamental process of tidal heating in the thermal and orbital evolution of celestial bodies.
Article
Geosciences, Multidisciplinary
Y. Xu, Z. H. Yao, B. Zhang, P. A. Delamere, L. C. Ray, W. R. Dunn, S. V. Badman, E. H. Feng, Z. Q. Zheng, S. J. Bolton, D. Grodent, B. Bonfond, Y. Wei
Summary: By using joint observations from Juno and the Hubble Space Telescope, this study statistically investigates the relationship between auroral power and current sheet variations under different solar wind conditions. The researchers found that during global main auroral brightening events, which are closely connected to solar wind compressions, the dawn side current sheet becomes substantially thinner compared to times when a quiet auroral morphology is present. Furthermore, the total current intensity in the current sheet increases under solar wind compression conditions. These findings provide important observational evidence on how magnetospheric dynamics driven by solar wind behavior affect auroral activity, deepening our understanding of the coupling between Jupiter's magnetosphere and ionosphere.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
R. L. Guo, Z. H. Yao, D. Grodent, B. Bonfond, G. Clark, W. R. Dunn, B. Palmaerts, B. H. Mauk, M. F. Vogt, Q. Q. Shi, Y. Wei, J. E. P. Connerney, S. J. Bolton
Summary: By analyzing observations from the Hubble Space Telescope and the Juno spacecraft, this study demonstrates the evolution of a double-auroral arc on the dawnside of Jupiter and suggests that this evolution is likely a result of the non-steady progress of magnetic reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Engineering, Aerospace
Zhan Feng, Ming Xu, Kangkang Jian, Jian Li
Summary: Europa is an important target for exploring extraterrestrial life, and halo orbits are considered suitable locations for observation. However, halo orbits are naturally unstable and require stationkeeping. This study addresses the stationkeeping problem of halo orbits in the Jupiter-Europa system perturbed by the moon Io, assuming unknown mass and orbital rate of Io. A tight stationkeeping scheme is proposed, considering autonomous navigation and using estimated values of Io's mass and orbital rate to enhance control robustness and accuracy. The estimation accuracy is evaluated through Monte Carlo simulation.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Geochemistry & Geophysics
James Tuttle Keane, Katherine de Kleer, John Spencer
Summary: Io is an ideal natural laboratory to study tidal heating, extreme volcanism, and atmospheric-magnetosphere-surface interactions. The capabilities of existing spacecraft to investigate Io are limited, highlighting the need for a dedicated Io mission to fully utilize its scientific potential. Advanced technologies and coordinated observations from multiple spacecraft make a modern Io mission even more compelling.
Article
Geosciences, Multidisciplinary
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, R. J. Wilson
Summary: This study compares Hubble Space Telescope observations of Jupiter's FUV auroras with Juno spacecraft observations in the equatorial middle magnetosphere of Jupiter, and shows that bright patches on the auroras are associated with magnetospheric convection and plasma injections.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
V. Hue, G. R. Gladstone, C. K. Louis, T. K. Greathouse, B. Bonfond, J. R. Szalay, A. Moirano, R. S. Giles, J. A. Kammer, M. Imai, A. Mura, M. H. Versteeg, G. Clark, J. -c. Gerard, D. C. Grodent, J. Rabia, A. H. Sulaiman, S. J. Bolton, J. E. P. Connerney
Summary: The positions of Jupiter's satellites Io, Europa, and Ganymede vary with time, resulting in changes in the lead angles of their respective auroral footprints. This study provides an empirical model of the equatorial lead angles for the northern and southern hemispheres using spectral images collected by Juno-UVS. The lead angle measurements are used to estimate the travel times of Alfven waves between the three innermost Galilean moons and Jupiter's hemispheres.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
T. Tanaka, Y. Ebihara, M. Watanabe, S. Fujita, R. Kataoka
Summary: In this study, the complex interaction between solar wind and Jupiter's magnetic field is investigated using Magnetohydrodynamics (MHD) and current conservation equations in the ionosphere. The research focuses on the formation of Io plasma disk, plasma corotation, instabilities, radial diffusion, and plasmoid ejection. The results provide insights into the dynamics of Jupiter's magnetosphere-ionosphere system.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Tanaka, Y. Ebihara, M. Watanabe, S. Fujita, R. Kataoka
Summary: The study investigates the interaction between the solar wind, Jovian magnetosphere, and ionosphere through global magnetohydrodynamic simulation. The simulation successfully reproduces various phenomena such as the confinement of Jovian magnetic field, distributions of ions, interchange instability, and current system that maintains co-rotation. The transport mechanism of Io plasma gradually changes from the Io torus to the distant tail, with different dominant factors at different distances. The study also reveals the connection between field-aligned current and ionospheric emissions.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Phillip H. Phipps, Paul Withers, Dustin R. Buccino, Yu-Ming Yang, Marzia Parisi
Summary: This study reports measurements of the total electron content through the Io plasma torus by the Juno spacecraft, revealing that the torus locations depend on longitude, the peak total electron content values vary with time, and the scale heights may depend on longitude and/or time. Additional analysis of observations by the Juno spacecraft is needed to further understand the roles of longitude, time, and the Io phase angle in shaping the density structure of the Io plasma torus.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
F. Allegrini, W. S. Kurth, S. S. Elliott, J. Saur, G. Livadiotis, G. Nicolaou, F. Bagenal, S. Bolton, G. Clark, J. E. P. Connerney, R. W. Ebert, G. R. Gladstone, P. Louarn, B. H. Mauk, D. J. McComas, A. H. Sulaiman, J. R. Szalay, P. W. Valek, R. J. Wilson
Summary: This study investigates the electron partial densities and temperatures in Jupiter's main auroral emission region using data from the Jovian Auroral Distributions Experiment (JADE) on Juno. The results show that electron partial densities and temperatures exhibit consistent trends across different longitudes and hemispheres, with no significant correlation with radial distance.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
M. N. Chowdhury, T. S. Stallard, K. H. Baines, G. Provan, H. Melin, G. J. Hunt, L. Moore, J. O'Donoghue, E. M. Thomas, R. Wang, S. Miller, S. V. Badman
Summary: The Cassini spacecraft discovered that Saturn's magnetic field oscillates at a different rate than the planetary rotation. It is believed that this variation is caused by a polar twin-cell neutral weather system. Using spectral observations from the Keck Observatory in 2017, researchers derived ion velocity maps and found wind systems in Saturn's ionosphere that align with predicted neutral twin-vortex flow patterns. This study reveals the impact of neutral winds on Saturn's rotational period and introduces a previously unseen process within planetary atmospheres.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
M. Teramoto, Y. Miyoshi, A. Matsuoka, Y. Kasahara, A. Kumamoto, F. Tsuchiya, M. Nose, S. Imajo, M. Shoji, S. Nakamura, M. Kitahara, I. Shnohara
Summary: Using magnetic field and electron density data from the Arase satellite, this study investigates the spatial properties of Pi2 pulsations in relation to the plasmapause in the inner magnetosphere. The results show that high-coherence magnetic field disturbances are mainly identified in the radial and compressional components on the nightside in the pre-midnight sector. By determining the location of the plasmapause using electron densities, it is found that the high-coherence events exhibit specific power ratio and phase changes near the plasmapause, indicating excitation by the plasmaspheric virtual resonance mode on the nightside.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Yuki Nakamura, Koichiro Terada, Chihiro Tao, Naoki Terada, Yasumasa Kasaba, Francois Leblanc, Hajime Kita, Aoi Nakamizo, Akimasa Yoshikawa, Shinichi Ohtani, Fuminori Tsuchiya, Masato Kagitani, Takeshi Sakanoi, Go Murakami, Kazuo Yoshioka, Tomoki Kimura, Atsushi Yamazaki, Ichiro Yoshikawa
Summary: The study evaluates the contribution of meteoric ions to ionospheric conductance by developing an ionospheric model combining a meteoroid ablation model and a photochemical model. It finds that the largest contribution to Pedersen and Hall conductivities occurs in the meteoric ion layer at altitudes of 350-600 km due to the long lifetimes of meteoric ions. Including meteoric ions enhances Pedersen and Hall conductances by factors of 3 and 10 in different regions, impacting magnetospheric plasma convection.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Fukizawa, T. Sakanoi, Y. Miyoshi, Y. Kazama, Y. Katoh, Y. Kasahara, S. Matsuda, A. Kumamoto, F. Tsuchiya, A. Matsuoka, S. Kurita, S. Nakamura, M. Shoji, M. Teramoto, S. Imajo, I. Shinohara, S. -Y. Wang, S. W. -Y. Tam, T. -F. Chang, B. -J. Wang, C. -W. Jun
Summary: This study demonstrates the contribution of LBC, UBC, and ECH waves to pitch-angle scattering of electrons at different energy ranges, and reveals the occurrence of approaching strong diffusion caused by these waves. These findings are important for understanding the behavior of inner magnetospheric electrons.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Fuliang Xiao, Jiawen Tang, Sai Zhang, Qinghua Zhou, Si Liu, Yihua He, Qiwu Yang, Yoshiya Kasahara, Yoshizumi Miyoshi, Atsushi Kumamoto, Yosuke Nakamura, Fuminori Tsuchiya, Iku Shinohara, Satoko Nakamura
Summary: This study presents the first statistical analysis of the distribution of auroral kilometric radiation (AKR) in the northern and southern hemispheres using observations from the Arase satellite. The results show an asymmetric distribution of AKR between the two hemispheres, which enhances our understanding of AKR.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Review
Astronomy & Astrophysics
Tomoki Kimura, Yuka Fujii, Hajime Kita, Fuminori Tsuchiya, Hideo Sagawa
Summary: Low-frequency radio emissions from bodies in our solar system have significant implications for understanding their magnetosphere, atmosphere, surface, and interior. This review highlights key questions regarding the dynamics and evolution of these bodies, and explores the feasibility of using the Square Kilometre Array (SKA) for future observations.
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2023)
Article
Geochemistry & Geophysics
A. V. Rubtsov, M. Nose, A. Matsuoka, Y. Kasahara, A. Kumamoto, F. Tsuchiya, I. Shinohara, Y. Miyoshi
Summary: The radial distribution of ion mass density in the Earth's magnetosphere can differ from that of electrons when there is a localized enhancement of heavy ion flux, such as an oxygen torus. This difference is crucial for the study of ultra-low-frequency (ULF) waves, which rely on the Alfven velocity and mass density. One important consequence is the shift in the location of the plasmapause, which is considered as the resonator and generation area for ULF waves. In this study, we identified that a factor of 1.65 or more increase in the Alfven velocity within a radial distance of 0.5 RE corresponds to the classic definition of plasmapause, where the electron density drops by a factor of 5 or more within the same radial distance. This finding allows us to confidently use the Alfven velocity to detect the plasmapause even when heavier ions are included and a direct comparison with electron density is not possible.
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
(2023)
Article
Environmental Sciences
Desy Purnami Singgih Putri, Yoshiya Kasahara, Mamoru Ota, Shoya Matsuda, Fuminori Tsuchiya, Atsushi Kumamoto, Ayako Matsuoka, Yoshizumi Miyoshi
Summary: This paper proposes a technique to correct plasmaspheric electron density profiles using ray tracing and dispersion analyses of lightning whistlers. The Global Core Plasma Model and the International Reference Ionosphere are used as reference density profiles, and modifications are made to satisfy the dispersion characteristics of observed whistlers. The method is applied to two lightning whistler events and the effect of density modification on ray path delay time is analyzed.
Article
Astronomy & Astrophysics
D. P. Hartley, G. S. Cunningham, J. -f. Ripoll, D. M. Malaspina, Y. Kasahara, Y. Miyoshi, S. Matsuda, S. Nakamura, F. Tsuchiya, M. Kitahara, A. Kumamoto, I. Shinohara, A. Matsuoka
Summary: A new empirical density model is developed for the inner zone between 1 L < 3 by using plasma densities inferred from the upper hybrid resonance on Arase and hiss-inferred density values from Van Allen Probes. The model includes dependencies on L, magnetic latitude, and magnetic local time (MLT), and can provide density values in areas outside the validity region of many previous models, making it a useful resource for accurately determining diffusion coefficients and predicting electron dynamics and their lifetimes in the inner radiation belt.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Shin Sugo, Satoshi Kasahara, Yoshizumi Miyoshi, Yuto Katoh, Kunihiro Keika, Shoichiro Yokota, Tomoaki Hori, Yoshiya Kasahara, Shoya Matsuda, Ayako Matsuoka, Iku Shinohara, Fuminori Tsuchiya, Atsushi Kumamoto, Satoko Nakamura, Masahiro Kitahara
Summary: Plasmaspheric hiss waves play a crucial role in electron precipitation and the formation of the slot region in the Earth's radiation belt. Previous studies have shown that the intensity of whistler-mode waves and electron precipitation is influenced by electron density and background magnetic field strength. However, direct evidence of strong pitch angle scattering by hiss waves inside the plasmasphere has been lacking, and the simultaneous investigation of density and magnetic field structures with hiss wave enhancement and electron precipitation has not been conducted. Our study provides direct observations of the importance of electron density and its spatial structure in electron precipitation, and the occurrence of strong scattering up to a magnetic latitude of about 15°.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Zhiyang Xia, Lunjin Chen, Wenyao Gu, Richard B. Horne, Yoshizumi Miyoshi, Yoshiya Kasahara, Atsushi Kumamoto, Fuminori Tsuchiya, Satoko Nakamura, Masahiro Kitahara, Iku Shinohara
Summary: In this study, 3 years of data from the ERG/Arase satellite was used to analyze the meridional distribution of wave power from VLF ground transmitters in the inner magnetosphere. It was found that the intensity of NWC transmitter signals decreases as they propagate from the southern to the equatorial region, and then increases as they propagate to the northern region. Similar results were observed from Van Allen Probes' data within a narrower latitude range. A ray-tracing simulation of the transmitter emission propagation reproduced similar meridional wave power distribution. Similar latitudinal dependence was also found for NAA, NLK, and NLM transmitters.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Astronomy & Astrophysics
Lorenz Roth, H. Todd Smith, Kazuo Yoshioka, Tracy M. Becker, Aljona Bloecker, Nathaniel J. Cunningham, Nickolay Ivchenko, Kurt D. Retherford, Joachim Saur, Michael Velez, Fuminori Tsuchiya
Summary: In situ plasma measurements and remote mapping of energetic neutral atoms around Jupiter provide indirect evidence of enhanced neutral gas near the orbit of moon Europa. Observations by the Cosmic Origins Spectrograph (COS) of the Hubble Space Telescope (HST) from 2020 to 2021 do not detect any neutral gas emissions. Comparison with modeled emissions supports the previous findings that the torus is dilute and primarily consists of molecular hydrogen. Detection of sulfur ion emissions is consistent with emissions from the extended Io torus.
PLANETARY SCIENCE JOURNAL
(2023)
Article
Astronomy & Astrophysics
Asuka Hirai, Fuminori Tsuchiya, Takahiro Obara, Yuto Katoh, Yoshizumi Miyoshi, Kazuo Shiokawa, Yasumasa Kasaba, Hiroaki Misawa, Chae-Woo Jun, Satoshi Kurita, Martin G. G. Connors, Aaron T. T. Hendry, Atsuki Shinbori, Yuichi Otsuka, Takuya Tsugawa, Michi Nishioka, Septi Perwitasari, Jerry W. W. Manweiler
Summary: By analyzing ground and satellite observations of EMIC waves, researchers found that the increased frequency of intervals of pulsations of diminishing periods (IPDPs) is caused by an inward shift of the EMIC wave source region, which is influenced by the enhanced convection electric field. This inward shift allows EMIC waves to scatter relativistic electrons over a wide range of radial distances during IPDP events. The study also suggests a possible contribution of EMIC waves to outer radiation belt loss during the main phase of geomagnetic storms.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Shinnosuke Satoh, Fuminori Tsuchiya, Shotaro Sakai, Yasumasa Kasaba, Rikuto Yasuda, Tomoki Kimura
Summary: Observations from the Hubble Space Telescope reveal an asymmetry in the morphology of the oxygen O-I] 135.6 nm emissions in Europa's atmosphere, which changes with the moon's position relative to Jupiter's magnetospheric plasma sheet. This study uses a test particle simulation to evaluate the cause of this north-south asymmetry and successfully reproduces it with the idea of a deceleration effect of the magnetospheric flux tube. However, additional model scenarios are needed to fully explain the observed brightness ratio.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
A. V. Rubtsov, M. Nose, A. Matsuoka, Y. Kasahara, A. Kumamoto, F. Tsuchiya, I. Shinohara, Y. Miyoshi
Summary: Magnetic storms and substorms cause global disturbances in the Earth's magnetosphere. Plasma clouds injected from the magnetotail during storm or substorm drift around the Earth and generate ultra-low frequency (ULF) waves via various mechanisms. The plasmasphere and its boundary, plasmapause, are special regions for ULF waves to interact with charged particles.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)