Article
Astronomy & Astrophysics
G. Q. Wang, M. Volwerk, M. Y. Wu, Y. F. Hao, S. D. Xiao, G. Wang, L. J. Liu, Y. Q. Chen, T. L. Zhang
Summary: The coronal heating region can generate mirror mode structures that evolve into magnetic holes, with ion vortexes playing a crucial role in their formation. These magnetic holes can be transported long distances by the solar wind, with recent observations revealing the presence of ion vortexes inside them. Understanding the role of ion vortexes in shaping magnetic holes may provide insights into their long-term survival in astrophysical plasmas.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Marissa F. Vogt, Matthew Rutala, Bertrand Bonfond, John T. Clarke, Luke Moore, Jonathan D. Nichols
Summary: Hubble Space Telescope images of Jupiter's UV aurora show that the main emission occasionally contracts or expands, shifting toward or away from the magnetic pole by several degrees in response to changes in the solar wind dynamic pressure and Io's volcanic activity. The study analyzes HST images from the Galileo era (1996-2003) and compares the latitudinal shifts of the Ganymede footprint and the main auroral emission. The research finds that the Ganymede footprint and main auroral emission typically, but not always, move together and their movements are weakly linked to changes in the current sheet strength measured by Galileo.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Sisti, S. Fadanelli, S. S. Cerri, M. Faganello, F. Califano, O. Agullo
Summary: This study investigates the development of coherent structures in space and astrophysical plasmas through hybrid-kinetic simulations of turbulence, characterizing their shape and comparing statistical properties with MMS data. The analysis validates the possibility of studying the overall shape of 3D structures using local methods and shows that the simulation results are consistent with observations from the MMS mission.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Geosciences, Multidisciplinary
R. Bandyopadhyay, D. J. McComas, J. R. Szalay, F. Allegrini, S. J. Bolton, R. W. Ebert, R. J. Wilson, D. J. Gershman
Summary: Power spectra of magnetic-field fluctuations near Jupiter have been analyzed since the early days of space exploration with Voyager and Ulysses flyby of Jupiter. However, power spectra of velocity and density fluctuations have not been as well studied, due to the lack of high-resolution measurements required to resolve a significant fraction of the inertial range. The investigation of fluid-scale turbulence in Jupiter's magnetosheath using measurements from the Jovian Auroral Distributions Experiment (JADE) instrument onboard Juno spacecraft revealed nearly Kolmogorov scaling of ion density and velocity spectra, indicating weakly compressible fluctuations and the presence of a scale-invariant cascade through the inertial range. This specific case study suggests the existence of Alfvenic Kolmogorov-type turbulence in at least some locations in Jupiter's magnetosheath.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Physics, Multidisciplinary
Joonas Nattila, Andrei M. Beloborodov
Summary: Magnetic energy around astrophysical compact objects can exceed plasma mass and energize the plasma through magnetic turbulence, but particle acceleration is not efficient.
PHYSICAL REVIEW LETTERS
(2022)
Article
Geosciences, Multidisciplinary
R. Bandyopadhyay, L. J. Begley, B. A. Maruca, D. J. McComas, J. R. Szalay, F. Allegrini, R. W. Ebert, D. J. Gershman, J. E. P. Connerney, S. J. Bolton
Summary: Most space plasmas are weakly collisional and exhibit non-Maxwellian velocity distributions and temperature anisotropy. Previous studies have shown that the range of ion temperature anisotropy becomes narrower as the parallel ion beta increases, attributed to the actions of kinetic microinstabilities. This study explores the beta-dependent limits on ion temperature anisotropy in Jupiter's magnetosheath.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Review
Astronomy & Astrophysics
Ian J. Cohen, Evan J. Smith, George B. Clark, Drew L. Turner, Donald H. Ellison, Ben Clare, Leonardo H. Regoli, Peter Kollmann, Daniel T. Gallagher, G. Allan Holtzman, Justin J. Likar, Takeshi Morizono, Matthew Shannon, Kimberly S. Vodusek
Summary: The PERSEUS mission concept aims to study multiple space physics science objectives at Uranus through a dedicated Heliophysics orbiter mission. Uranus's complex and dynamic magnetosphere provides a unique laboratory to study magnetospheric physics and its interactions with the solar wind, planet's atmosphere, satellites, and rings.
SPACE SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Ian J. Cohen, Drew L. Turner, Peter Kollmann, George B. Clark, Matthew E. Hill, Leonardo H. Regoli, Daniel J. Gershman
Summary: In situ exploration of Uranus has been limited, but new investigation suggests that energetic ions observed between its moons Miranda and Ariel may be introduced by a source from one of these moons. This finding reveals the importance of internal plasma sources in Uranus' magnetospheric dynamics and its strong radiation belts.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Nancy J. Chanover, James M. Bauer, John J. Blalock, Mitchell K. Gordon, Lyle F. Huber, Mia J. T. Mace, Lynn D. V. Neakrase, Matthew S. Tiscareno, Raymond J. Walker
Summary: While fewer missions have been conducted to the outer Solar System compared to the inner Solar System, these missions to the giant planets have provided valuable data that continue to shape our understanding of these complex systems. The data are stored in national and international planetary archives and can be accessed through the NASA Planetary Data System (PDS). The PDS will serve as the main repository for future missions' data and support research on the interpretation of the existing data.
Article
Astronomy & Astrophysics
L. M. Zelenyi, H. Malova, M. Leonenko, E. E. Grigorenko, V. Yu Popov
Summary: This paper presents an analytical self-consistent model of a super thin electron current sheet (STCS) supported by magnetized electrons within a proton structure. By considering the anisotropy of electron distribution and magnetic field shear, the structure of the embedded STCS can be described by a simple nonlinear equation, allowing for the estimation of STCS thickness scaling due to the coupling of electron and ion domains. The theoretical results are in good agreement with spacecraft observations in Earth's magnetotail.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Sitnov, H. Arnold
Summary: The magnetotail current in the substorm growth phase has a multiscale structure with a thin ion-scale current sheet embedded into a much thicker sheet. This structure is crucial for tail stability and onset conditions for magnetospheric substorms. The observed length of the thin current sheets cannot be explained by isotropic plasma models. Plasma observations show weak anisotropy of the ion species and insufficient electron contribution to explain the force balance discrepancy.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Physics, Applied
Justin M. Little, Gordon I. McCulloh, Cameron Marsh
Summary: This study investigates the formation of current sheets in inductive pulsed plasma thrusters (IPPTs). It finds that non-equilibrium ionization processes play an important role in the plasma impermeability to electromagnetic fields and propellant mass. The dynamics of electron heating during the early phase of the inductive current cycle are identified as the dominant contributors to current sheet formation.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Astronomy & Astrophysics
A. R. Azari, E. Abrahams, F. Sapienza, D. L. Mitchell, J. Biersteker, S. Xu, C. Bowers, F. Perez, G. A. DiBraccio, Y. Dong, S. Curry
Summary: The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission has provided valuable insights into the dynamic space environment of Mars. The study reveals unexpected characteristics of Mars' magnetic field, influenced by the interplanetary magnetic field, remanent crustal fields, and an underestimated induced effect. The findings also indicate the significant influence of the crustal field and the IMF direction on the magnetotail morphology of Mars.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
Li-Jen Chen, Jonathan Ng, Yuri Omelchenko, Shan Wang
Summary: The study predicts that foreshock turbulence can reach the magnetopause and lead to reconnection and Earth-sized indents. In the simulation, both the IMF and solar wind are constant, and all dynamics are generated by foreshock instabilities. A reconnection example is used to demonstrate how turbulence can create large magnetic shear angles across the magnetopause to induce local bursty reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Xin An, Anton Artemyev, Vassilis Angelopoulos, Andrei Runov, Sergey Kamaletdinov
Summary: Through particle-in-cell simulations, we have discovered two-dimensional force-free current sheets, which have a magnetic field component normal to the current sheets. While one-dimensional force-free current sheets have been extensively studied, the attention towards their two-dimensional counterparts has been insufficient. Our simulations demonstrate the existence of kinetic force-free current sheets, with established kinetic equilibria at the end. Despite the maintained alignment of currents in the equilibrium state, the velocity distribution functions of ions and electrons evolve from initial drifting Maxwellians to final time-stationary Vlasov state.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Fluids & Plasmas
S. R. Kamaletdinov, I. Y. Vasko, R. Wang, A. V. Artemyev, E. V. Yushkov, F. S. Mozer
Summary: This study analyzes about 100 bipolar structures of positive polarity detected by the Magnetospheric Multiscale spacecraft in the Earth's bow shock, suggesting that these structures are slow electron holes rather than ion-acoustic solitons. The presence of transverse instability significantly limits the lifetime of large-amplitude electron holes above a certain threshold.
PHYSICS OF PLASMAS
(2022)
Article
Astronomy & Astrophysics
O. W. Roberts, O. Alexandrova, L. Sorriso-Valvo, Z. Voeroes, R. Nakamura, D. Fischer, A. Varsani, C. Philippe Escoubet, M. Volwerk, P. Canu, S. Lion, K. Yearby
Summary: In this study, the turbulence in the slow solar wind is investigated using multi-spacecraft measurements for different satellite configurations. Differences in two time-lagged magnetic field measurements (time-lags) and in magnetic field measurements between spacecraft pairs (space-lags) are compared. The intermittency of magnetic field fluctuations is analyzed. Differences are observed between the time-lagged measurements and the spatially lagged measurements when the spacecraft pairs are transverse to the flow.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
L. M. Zelenyi, H. Malova, M. Leonenko, E. E. Grigorenko, V. Yu Popov
Summary: This paper presents an analytical self-consistent model of a super thin electron current sheet (STCS) supported by magnetized electrons within a proton structure. By considering the anisotropy of electron distribution and magnetic field shear, the structure of the embedded STCS can be described by a simple nonlinear equation, allowing for the estimation of STCS thickness scaling due to the coupling of electron and ion domains. The theoretical results are in good agreement with spacecraft observations in Earth's magnetotail.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Engineering, Aerospace
Nina Sarah Muehlich, Harald Jeszenszky, Johanna Fries, Gerhard Fremuth, Joachim Gerger, Florin Plesescu, Manfred Steller, Bernhard Seifert, Rumi Nakamura, Fabrice Cipriani
Summary: The active spacecraft potential control (ASPOC) system, developed in the 1990s, effectively neutralizes the spacecraft's potential through emission of positive ions. The next generation ASPOC system (ASPOC-NG) has been developed over the last three years, with tests conducted on three emission technologies and optimizations made on mass and power consumption. Coupling tests of the modules and electronics control unit have demonstrated excellent results in terms of range, accuracy, and lifetime.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Astronomy & Astrophysics
W. -l. Teh, T. K. M. Nakamura, S. Zenitani, T. Umeda, R. Nakamura
Summary: This study investigates the energy conversion process during the coalescence of magnetic islands using a two-dimensional kinetic simulation. The results reveal the presence of energy dynamo and energy dissipation during this process, which have a significant impact on particle acceleration. The simulated energy conversion signatures are also compared favorably with observed magnetic islands.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Fluids & Plasmas
T. K. M. Nakamura, W. -l. Teh, S. Zenitani, T. Umeda, M. Oka, H. Hasegawa, A. M. Veronig, R. Nakamura
Summary: Magnetic reconnection is a fundamental process that converts magnetic energy to plasma kinetic energy in collisionless plasmas. This study focuses on the coalescence of multiple magnetic islands and examines the spatial dimensions of the internal structures. It is found that the dimensions depend on the initial thickness of the current sheet and the number of coalescing islands. The study also discovers that the horizontal dimension controls the evolution time scale, while the vertical dimension affects the reconnection maturity and particle heating.
PHYSICS OF PLASMAS
(2023)
Article
Astronomy & Astrophysics
D. Teubenbacher, O. W. Roberts, R. Nakamura, Y. Narita, Z. Voeroes, K. Torkar, P. -A. Lindqvist, R. E. Ergun
Summary: In this study, the Magnetospheric Multiscale (MMS) mission data is utilized to estimate electron density and analyze compressive turbulence in the Earth's magnetosheath. The MMS Solar Wind Turbulence Campaign in February 2019 provided multiple spacecraft measurements at varying distances for a detailed investigation. The derived electron density data has higher temporal resolution compared to plasma instruments, allowing examination of fluctuations at sub-ion scales. The findings suggest different drivers in the strongly compressive magnetosheath and the weakly compressive solar wind, with compressive structures potentially playing significant roles.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Iannis Dandouras, Matt G. G. T. Taylor, Johan De Keyser, Yoshifumi Futaana, Ruth A. Bamford, Graziella Branduardi-Raymont, Jean-Yves Chaufray, Dragos Constantinescu, Elisabetta De Angelis, Pierre Devoto, Jonathan Eastwood, Marius Echim, Philippe Garnier, Benjamin Grison, David Hercik, Helmut Lammer, Andre Laurens, Francois Leblanc, Anna Milillo, Rumi Nakamura, Lubomir Prech, Elias Roussos, Stepan Stverak, Julien Forest, Arnaud Trouche, Sebastien L. G. Hess, Jean-Charles Mateo-Velez, James Carpenter, Josef Winter
Summary: The Lunar Orbital Platform - Gateway (LOP-Gateway), assembled and operated by NASA and international partner organizations, offers new opportunities for scientific research in the vicinity of the Moon. It provides a unique location to study the deep space plasma environment and its interaction with the lunar surface and exosphere. This paper explores the potential of externally mounted payloads on the Gateway for space plasma physics research and the impact of the space environment on an inhabited platform.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Astronomy & Astrophysics
O. W. Roberts, Y. Narita, R. Nakamura, Z. Voeroes
Summary: This study uses density measurements deduced from spacecraft potential to investigate the power spectral density of compressive fluctuations in the solar wind. It is found that the morphology of density spectra differs from that of trace magnetic field fluctuations, with a flattening often observed between inertial and kinetic ranges. The spectral break in magnetic field fluctuations occurs near the expected frequency for cyclotron resonance or magnetic reconnection, while the spectral break in density fluctuations often occurs at a higher frequency compared to the trace magnetic field.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Geosciences, Multidisciplinary
K. A. Blasl, T. K. M. Nakamura, R. Nakamura, A. Settino, H. Hasegawa, Z. Voeroes, M. Hosner, D. Schmid, M. Volwerk, Owen W. Roberts, E. Panov, Yi-Hsin Liu, F. Plaschke, J. E. Stawarz, J. C. Holmes
Summary: This article presents observations of an electron-scale reconnecting current sheet in the mixing region along the trailing edge of a Kelvin-Helmholtz vortex. Consistencies between the observations and a realistic simulation indicate a temporal evolution of the observed electron-scale reconnection current sheet. The multi-scale and inter-process character of this event is important in understanding plasma mixing connected to the Kelvin-Helmholtz instability and the temporal evolution of electron-scale reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Physics, Fluids & Plasmas
K. Torkar, R. Nakamura, O. W. Roberts, H. Jeszenszky, P. -a. Lindqvist, Y. Khotyaintsev, B. L. Giles, A. C. Barrie
Summary: The four spacecraft of the NASA Magnetospheric Multiscale (MMS) mission utilize indium ion beams to decrease the positive potential. The active spacecraft potential control (ASPOC) instruments have been in operation for over 16,000 hours per spacecraft since the nominal mission began in September 2015 until the end of 2021. Statistical analysis of data collected over six years, with over 50,000 hours in scientific regions of interest, provides insights into the interdependencies between the potential and ambient plasma. This article presents the derivation of the photoelectron energy spectrum from the correlation between the potential and plasma data obtained by the fast plasma instrument, both with and without controlled potential, along with estimating the electric capacitance of the spacecraft system based on time constants during relaxation of the controlled potential when the active control instrument is turned off.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2023)
Article
Astronomy & Astrophysics
S. W. Alqeeq, O. Le Contel, P. Canu, A. Retino, T. Chust, L. Mirioni, A. Chuvatin, R. Nakamura, N. Ahmadi, F. D. Wilder, D. J. Gershman, Yu. V. Khotyaintsev, P. -A. Lindqvist, R. E. Ergun, J. L. Burch, R. B. Torbert, S. A. Fuselier, C. T. Russell, H. Y. Wei, R. J. Strangeway, K. R. Bromund, D. Fischer, B. L. Giles, Y. Saito
Summary: In this study, a statistical analysis of equatorial dipolarization fronts (DFs) detected by the Magnetospheric Multiscale mission during the 2017 magnetotail season was conducted. Two distinct classes of DFs were identified: class I, which corresponds to the standard DF properties and energy dissipation, and class II, a new class that features a bump in the magnetic field, a minimum in ion and electron pressures, and a reversal of the energy conversion process. The study also reveals that the energy conversion processes of these two classes of DFs differ in the spacecraft frame and fluid frame, mainly due to variations in the electric fields.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Niklas Grimmich, Ferdinand Plaschke, Martin O. Archer, Daniel Heyner, Johannes Z. D. Mieth, Rumi Nakamura, David G. Sibeck
Summary: The magnetopause (MP) is primarily determined by the pressure balance between the solar wind and the magnetosphere. The boundary can move due to different solar wind conditions and transient foreshock phenomena, resulting in unusually large or small distances from the Earth. In this study, we investigate the occurrence of extreme MP distortions under specific solar wind conditions and identify several parameters, such as IMF magnitude, cone angle, velocity, Alfven Mach number, and temperature, that are linked to these extreme events. The findings have implications for future magnetopause models and the reconstruction of MP locations using soft X-ray images for missions like SMILE.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Kevin J. Genestreti, Charles J. Farrugia, San Lu, Sarah K. Vines, Patricia H. Reiff, Tai Phan, Daniel N. Baker, Trevor W. Leonard, James L. Burch, Samuel T. Bingham, Ian J. Cohen, Jason R. Shuster, Daniel J. Gershman, Christopher G. Mouikis, Anthony J. Rogers, Roy B. Torbert, Karlheinz J. Trattner, James M. Webster, Li-Jen Chen, Barbara L. Giles, Narges Ahmadi, Robert E. Ergun, Christopher T. Russell, Robert J. Strangeway, Rumi Nakamura
Summary: This study analyzes a magnetotail reconnection event that occurred on 3 July 2017, and investigates the processes that thinned and stretched the cross-tail current layer. It was found that the current sheet thinning was initiated by a transient solar wind pressure pulse and continued despite the decrease in magnetotail and solar wind pressures.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Kevin J. Genestreti, Charles J. Farrugia, San Lu, Sarah K. Vines, Patricia H. Reiff, Tai Phan, Daniel N. Baker, Trevor W. Leonard, James L. Burch, Samuel T. Bingham, Ian J. Cohen, Jason R. Shuster, Daniel J. Gershman, Christopher G. Mouikis, Anthony J. Rogers, Roy B. Torbert, Karlheinz J. Trattner, James M. Webster, Li-Jen Chen, Barbara L. Giles, Narges Ahmadi, Robert E. Ergun, Christopher T. Russell, Robert J. Strangeway, Rumi Nakamura, Drew L. Turner
Summary: The local dynamics of magnetotail reconnection onset were analyzed using MMS data, revealing features such as cross-tail current sheet thinning, flapping wave growth, and electron tearing. Multiple magnetic islands were detected coincident with the growth of the ion exhaust. Two secondary reconnection sites were found embedded within the primary X-line.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
