Article
Physics, Fluids & Plasmas
J. L. Burch, K. J. Genestreti, S. V. Heuer, A. Chasapis, R. B. Torbert, D. J. Gershman, R. Bandyopadhyay, C. J. Pollock, W. H. Matthaeus, T. K. M. Nakamura, J. Egedal
Summary: On July 11, 2017, the four Magnetospheric Multiscale spacecraft encountered a reconnection region in the Earth's magnetospheric tail. This paper reports on the investigation of the conversion of electromagnetic energy to electron kinetic energy and the conversion of electron beam energy to electron thermal energy via pressure-strain interaction. The main result is that omnidirectional, compressive dissipation of electron energy dominates in the positive J center dot E region, and incompressive parallel dissipation dominates in the inflow region where J center dot E is small.
PHYSICS OF PLASMAS
(2023)
Article
Astronomy & Astrophysics
D. B. Korovinskiy, S. A. Kiehas, E. V. Panov, V. S. Semenov, N. V. Erkaev, A. V. Divin, I. V. Kubyshkin
Summary: This study focuses on the reconstruction of magnetic configuration in the magnetic reconnection electron diffusion region, introducing a new reconstruction model independent of divergence of the electron pressure tensor and reconnection electric field. The model is tested on a magnetotail reconnection event observed by the MMS spacecraft, showing improved accuracy in electron velocity reconstruction and suggesting a new technique to estimate the guide field based on magnetic potential reconstruction. The study highlights the significance of electron inertia in the physics of the electron diffusion region, leading to considerable improvement in reconstruction accuracy.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yongyuan Yi, Y. Pang, Liangjin Song, Runqing Jin, Xiaohua Deng
Summary: We investigate the energy conversion in the turbulent region downstream of the reconnection front through 2.5D particle-in-cell simulations. Our findings reveal that a significant amount of magnetic energy is transferred into plasma both in the exhaust region and the turbulent region, which is formed due to the electron Kelvin-Helmholtz instability. Unlike the energy conversion in the exhaust region, the energy conversion in the turbulent region is mainly balanced by its in-plane component. Furthermore, the time evolution of the integrated energy conversion in the turbulent region is strongly correlated with the electron Kelvin-Helmholtz instability and secondary reconnection. The energy is transferred to ions through a nonideal electric field associated with the electron vortices formed during the development of the instability.
ASTROPHYSICAL JOURNAL
(2023)
Article
Geosciences, Multidisciplinary
Meng Zhou, Hengyan Man, Yan Yang, Zhihong Zhong, Xiaohua Deng
Summary: This paper evaluates quasi-viscous dissipation in the electron diffusion region at Earth's magnetopause and reveals intriguing findings, such as electrons being cooled rather than heated in a large portion of the diffusion region.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
X. C. Dong, M. W. Dunlop, T. Y. Wang, J. S. Zhao, H. S. Fu, Z. Z. Chen, C. T. Russell, B. Giles, R. Ergun, P. Lindqvist
Summary: Utilizing MMS data, this study investigates the energy dissipation in a magnetopause reconnection electron diffusion region event with moderate guide field. While a quasi-homogeneous magnetic and current structure is formed in the diffusion region, differences in energy dissipations detected by each spacecraft are attributed to the temporal or spatial effect of the out-of-plane reconnection electric field within the dissipation region.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Gina A. DiBraccio, Norberto Romanelli, Charles F. Bowers, Jacob R. Gruesbeck, Jasper S. Halekas, Suranga Ruhunusiri, Tristan Weber, Jared R. Espley, Shaosui Xu, Janet G. Luhmann, Yuki Harada, Eduard Dubinin, Gang Kai Poh, David A. Brain, Shannon M. Curry
Summary: The Martian magnetotail exhibits a highly twisted configuration, which is influenced by changes in the polarity of the interplanetary magnetic field. The degree of twisting is mainly determined by the orientation of the interplanetary magnetic field and the distance from the tail. Furthermore, the crustal magnetic fields on the surface of Mars also play a significant role in the magnetospheric structure.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
S. E. Milan, M. K. Mooney, G. E. Bower, M. G. G. T. Taylor, L. J. Paxton, I. Dandouras, A. N. Fazakerley, C. M. Carr, B. J. Anderson, S. K. Vines
Summary: We investigated a 15-day period in October 2011 and found weak cusp-aligned arc (CAA) emissions in the polar regions when the interplanetary magnetic field (IMF) clock angle was small. Simultaneous observations of ions and electrons showed that dense plasma was observed even far from the equatorial plane of the tail. We interpret the observations as evidence of trapped plasma on closed field lines, suggesting that the magnetosphere was almost entirely closed during these periods.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
V. A. Sergeev, S. Apatenkov, R. Nakamura, F. Plaschke, W. Baumjohann, E. Panov, I. Kubyshkin, Y. Khotyaintsev, J. L. Burch, B. L. Giles, C. T. Russell, R. B. Torbert
Summary: The region surrounding the reconnection separatrix features various particle and wave transient characteristics, with patterns and parameters influenced by the distance from the active neutral line. Studies on entries into the plasma sheet boundary layer show distinct regions like EBL, PBL, and HR, each with unique features such as accelerated electron beams, hot proton beams, and intense Hall-like Ez perturbations. These findings hold true even at large distances from the reconnection region, with variations in time scales and spatial patterns.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
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)
Article
Geosciences, Multidisciplinary
M. Hubbert, Y. Qi, C. T. Russell, J. L. Burch, B. L. Giles, T. E. Moore
Summary: This report examines tail current sheets supported only by electron currents in Earth's magnetotail. Three of these current sheets are interpreted in terms of the time-evolution of reconnection onset, showing evidence of parallel electron heating, perpendicular ion heating, and current sheet expansion. The data suggests that electron-only reconnection can act as a precursor to electron-ion reconnection, but also that it is more than merely a precursor to ion reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Kun Bai, Yiqun Yu, Huishan Fu, Fan Gong, Jinbin Cao
Summary: Magnetic flux ropes (MFRs) are helical structures in the solar-terrestrial space that play a crucial role in particle acceleration and energy transport. This study uses numerical models and simulations to demonstrate that large-scale MFRs can lead to ion acceleration and bring energetic plasma into the inner magnetosphere.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Y. Y. Wei, S. Y. Huang, K. Jiang, Z. G. Yuan, S. B. Xu, J. Zhang, Q. Y. Xiong, Z. Wang, R. T. Lin, L. Yu, Y. Y. Li, C. M. Wang, G. J. Song
Summary: Our study performs a direct quantitative analysis to reveal the acceleration process of energetic electrons at the dipolarization front (DF) using high-time-resolution data. The analysis shows that these electrons at the front could be locally accelerated to over 100 keV by betatron acceleration. The temperature anisotropy formed via the betatron mechanism provides the free energy to excite whistler waves at the DF. Our study provides strong direct evidence for the local electron acceleration at the DF for the first time.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Fluids & Plasmas
S. Adhikari, T. N. Parashar, M. A. Shay, W. H. Matthaeus, P. S. Pyakurel, S. Fordin, J. E. Stawarz, J. P. Eastwood
Summary: Using simulations of strong turbulence and reconnection, a study compares the cross-scale transfer of energy in the two systems and finds that the energy transfer structure is very similar in both cases. In the case of reconnection, the time evolution of energy transfer is correlated with the reconnection rate, providing explicit evidence that reconnection dynamics fundamentally involves turbulence-like energy transfer.
Article
Astronomy & Astrophysics
J. W. Gao, Z. J. Rong, M. Persson, G. Stenberg, Y. C. Zhang, L. Klinger, X. D. Wang, D. Liu, Y. Wei, S. Barabash, Y. Futaana
Summary: Utilizing in situ observations from Venus Express, evidence of magnetic reconnection occurring in the Venusian magnetotail has been reported. The crossing of the ion diffusion region provides support for the presence of magnetic reconnection, with observed ion flows confirming expected characteristics of reconnection outflow. This discovery highlights the Venusian magnetotail as a unique space laboratory for studying the reconnection process.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Yash Sarkango, James A. Slavin, Xianzhe Jia, Gina A. DiBraccio, Daniel J. Gershman, John E. P. Connerney, William S. Kurth, George B. Hospodarsky
Summary: Two small ion-inertial scale magnetic flux ropes were identified in the Juno magnetic field measurements in Jupiter's magnetotail. These structures could potentially play a significant role in mass loss through plasmoid ejection in the magnetosphere, highlighting the differences in magnetic reconnection processes between Jupiter and other magnetized planets like Earth and Mercury. Further studies are needed to fully understand the implications of these small-scale flux ropes on Jupiter's magnetospheric dynamics.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Physics, Fluids & Plasmas
Tohru Shimizu, Koji Kondoh, Seiji Zenitani
PHYSICS OF PLASMAS
(2017)
Article
Physics, Fluids & Plasmas
Seiji Zenitani
PLASMA PHYSICS AND CONTROLLED FUSION
(2018)
Article
Astronomy & Astrophysics
Seiji Zenitani, Hiroshi Hasegawa, Tsugunobu Nagai
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2017)
Article
Physics, Fluids & Plasmas
M. Hosseinpour, Y. Chen, S. Zenitani
PHYSICS OF PLASMAS
(2018)
Article
Physics, Fluids & Plasmas
Seiji Zenitani, Takayuki Umeda
PHYSICS OF PLASMAS
(2018)
Article
Astronomy & Astrophysics
Yosuke Matsumoto, Yuta Asahina, Yuki Kudoh, Tomohisa Kawashima, Jin Matsumoto, Hiroyuki R. Takahashi, Takashi Minoshima, Seiji Zenitani, Takahiro Miyoshi, Ryoji Matsumoto
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2019)
Article
Computer Science, Interdisciplinary Applications
Seiji Zenitani, Tsunehiko N. Kato
COMPUTER PHYSICS COMMUNICATIONS
(2020)
Article
Astronomy & Astrophysics
Wai-Leong Teh, Seiji Zenitani
Summary: A new reconstruction method incorporating alpha(B) has been developed and tested for time-dependent mirror structures, showing reasonable results and outperforming other isotropic pressure and vector potential-based reconstruction methods.
EARTH AND SPACE SCIENCE
(2021)
Article
Physics, Fluids & Plasmas
Genta Ueno, Seiji Zenitani
Summary: In this study, a mixture model composed of relativistic Maxwellian distributions is proposed for analyzing distribution functions of relativistic plasma. The basic properties of the relativistic Maxwellian distribution and its maximum likelihood estimation are summarized. An expectation-maximization algorithm is developed for estimating the parameters of the relativistic Maxwellian mixture model (R-MMM), which is then applied to separate a simulated distribution function into two components, revealing differences in bulk velocity and similarity in temperatures.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
Seiji Zenitani, Shin'ya Nakano
Summary: This paper presents a procedure for loading particle velocities from a relativistic kappa distribution in particle-in-cell and Monte Carlo simulations. The procedure is based on the rejection method and the beta prime distribution. It successfully reproduces the relativistic kappa distribution, including the power-law tail.
PHYSICS OF PLASMAS
(2022)
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
Seiji Zenitani, Takahiro Miyoshi
ASTROPHYSICAL JOURNAL LETTERS
(2020)
Article
Astronomy & Astrophysics
Wai-Leong Teh, Seiji Zenitani
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Wai-Leong Teh, Seiji Zenitani
ASTROPHYSICAL JOURNAL
(2019)