Article
Geosciences, Multidisciplinary
S. Y. Huang, Y. Y. Wei, J. S. Zhao, Z. G. Yuan, X. H. Deng, K. Jiang, S. B. Xu, J. Zhang, Q. Y. Xiong, Z. H. Zhang, L. Yu, R. T. Lin
Summary: KSMHs in the terrestrial foreshock region were studied based on Magnetospheric Multiscale data, where most of them are accompanied by electron vortices. Inside the magnetic holes, electron fluxes at 90 degrees of pitch angle enhance, perpendicular and total electron temperatures increase, while parallel electron temperature slightly decreases. A novel phenomenon is revealed that many observed KSMHs may be moving toward the Sun in the plasma flow frame, detected for the first time in the foreshock region.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Wenqing Ma, Meng Zhou, Zhihong Zhong, Xiaohua Deng
Summary: This article presents a statistical study on electron acceleration in Earth's magnetotail using in situ satellite observations. The study finds that larger acceleration rates tend to occur in outflows with higher speeds. The mechanisms of betatron and first-order Fermi acceleration are intensified near the neutral sheet, while E (divide divide) acceleration is significant not only near the neutral sheet but also in the separatrix region. The study also suggests that acceleration near the X line is comparable to that in the outflow, contradicting previous studies.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Shan Wang, Yan Yang
Summary: We perform a simulation to study electron heating associated with magnetic reconnection in turbulent plasmas. The simulation shows that the electron temperature is higher near reconnection sites compared to other areas, and the heating rate of the electrons is influenced by the average ion Alfvén speed. We also investigate the mechanisms of electron energization and find that different mechanisms dominate at different stages of the reconnection process. The thickness of the current sheets plays a critical role in initiating reconnection.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
C. -h. Gao, B. -b. Tang, X. -c. Guo, W. Y. Li, Y. V. Khotyaintsev, D. B. Graham, D. L. Turner, Z. W. Yang, C. Wang
Summary: Agyrotropic electron distributions, previously believed to indicate electron diffusion regions of magnetic reconnection, have been found to also occur at non-reconnecting magnetopause boundaries due to the electron finite gyroradius effect. This study presents observations in the Earth's magnetotail that show the presence of agyrotropic electron distributions in the foreshock region. These distributions are generated by the electron finite gyroradius effect after magnetic curvature scattering at a thin electron-scale boundary, without any signatures of magnetic reconnection. Test-particle simulations confirm the generation of agyrotropic electron distributions. These findings suggest that such distributions can occur more widely in the space plasma environment.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Z. H. Zhong, M. Zhou, D. B. Graham, Yu. V. Khotyaintsev, Y. F. Wu, O. Le Contel, H. M. Li, X. Tao, R. X. Tang, X. H. Deng
Summary: This paper investigates the whistler-mode waves within an electron-scale current sheet and measures their dispersion relation for the first time. The study shows that the drifting electron component along the magnetic field critically modifies the dispersion relation and demonstrates that these whistler waves propagate into the diffusion region from outside rather than being locally excited.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Z. C. Tian, M. Zhou, H. Y. Man, Z. H. Zhong, X. H. Deng, D. J. Gershman, Y. V. Khotyaintsev, C. T. Russell
Summary: This paper presents the simultaneous observation of the inner and outer electron diffusion region (EDR) in magnetic reconnection with a large guide field at the dayside magnetopause by the magnetospheric multiscale (MMS) spacecraft. The inner EDR is characterized by positive J·E', while the outer EDR is manifested by negative J·E' and opposite out-of-plane electric field. The observation of bidirectional accelerated electron jets on the opposite side of the X-line is significant, and the fortuitous formation of MMS provides estimates for the length of the inner EDR and the reconnection rate.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Zhi Li, Mao Zhang
Summary: Magnetic holes are commonly found in Earth's magnetosphere plasma system. Understanding their formation mechanisms and their impact on the background plasma is crucial for gaining insight into energy conversion in near-earth space environments. This study provides clear evidence that a kinetic-scale magnetic hole occurs in the separatrix region of asymmetry reconnection at the Earth's magnetopause, suggesting a broader connection between magnetic holes and reconnection. High-resolution measurements show that electrons along the separatrix region are trapped and significantly thermalized by the magnetic hole. Observations indicate that a separatrix region with significant shear flow can create favorable conditions for stable magnetic holes, which can continuously generate high-energy electrons.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(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
J. M. Schroeder, J. Egedal, G. Cozzani, Yu Khotyaintsev, W. Daughton, R. E. Denton, J. L. Burch
Summary: This study analyzes in-situ spacecraft observations from Earth's magnetotail and maps them onto a 2D spatial domain to study the process of magnetic reconnection. The results show that, despite perturbations from 3D dynamics, the structure of the electron diffusion region remains consistent with 2D kinetic simulation, validating the effectiveness of 2D kinetic and laminar reconnection models.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Engineering, Aerospace
Z. Z. Chen, J. Yu, C. M. Liu, J. Wang, J. Cui, J. B. Cao
Summary: Cold plasmas play a crucial role in modifying dynamical processes during magnetic reconnection. This study presents observations of cold electrons originating from the terrestrial lobe at the magnetotail reconnection separatrix region. The number density and current density carried by these cold electrons demonstrate their significant impact on the reconnection process.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
K. Jiang, S. Y. Huang, Z. G. Yuan, Q. Y. Xiong, Y. Y. Wei
Summary: With high-resolution data from the MMS mission, a tilted ion-scale flux rope is observed in the tailward outflow of a magnetic reconnection in the terrestrial magnetotail, indicating the extension of the X-line in the dawn-dusk direction. The observed electron vortex embedded in the flux rope generates an induced magnetic field with the same direction as the axial component, contributing to the enhancement of the magnetic flux carried by the flux rope.
GEOPHYSICAL RESEARCH LETTERS
(2023)
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
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
Z. Z. Chen, H. S. Fu, Z. Wang, Z. Z. Guo, Y. Xu, C. M. Liu
Summary: This study presents the first observation of a magnetic flux rope (MFR) inside an electron diffusion region (EDR), confirming its crucial role in magnetic reconnection. By observing and analyzing the structure and energy dissipation of MFR, it helps to understand the modulation of the electric field in EDR by MFR.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Y. Zhong, Y. Dai, M. D. Ding
Summary: Recent observations in extreme-ultraviolet wavelengths have revealed a new late phase in some solar flares, with different production mechanisms such as long-lasting cooling or additional heating. Additionally, an enhancement of the envelope magnetic field above the active region may facilitate a more prompt and energetic heating of the late phase emissions.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
J. Zhang, S. Y. Huang, F. Sahraoui, N. Andres, Z. G. Yuan, K. Jiang, S. B. Xu, Y. Y. Wei, Q. Y. Xiong, Z. Wang, R. T. Lin, L. Yu
Summary: The topology of magnetic and velocity fields at the kinetic scales in nearly incompressible magnetosheath plasma turbulence is investigated using high-resolution data from the Magnetospheric MultiScale mission. Joint probability distribution functions of geometric invariants characterizing the magnetic and velocity fields gradient tensor are computed. The topological features of the gradient tensors show axisymmetric distribution, indicating differences from hydrodynamic and magnetohydrodynamic turbulence, and a strong correlation between straining and rotational parts suggests dominant sheet-like structures in the dissipation of incompressible plasma turbulence at the kinetic scales.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Q. Y. Xiong, S. Y. Huang, Z. G. Yuan, K. Jiang, Y. Y. Wei, S. B. Xu, J. Zhang, Z. Wang, R. T. Lin, L. Yu
Summary: This paper introduces an approach that implements full kinetic particle-in-cell simulations on GPU architecture devices using the CUDA Fortran language programming. By using the latest high-performance computing NVIDIA GPUs, the program can significantly speed up the computing process compared to running on a single core of an Intel Xeon Gold processor. This scheme improves accessibility to simulation results and provides valuable assistance in studying physical processes.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
R. T. Lin, S. Y. Huang, Z. G. Yuan, K. Jiang, S. B. Xu, Y. Y. Wei, Q. Y. Xiong, J. Zhang, Z. Wang, L. Yu
Summary: Intense electromagnetic energy conversion and local magnetic flux transport occur at reconnection fronts. Tailward RFs (TRFs) are observed in the Earth's magnetotail, characterized by enhanced negative magnetic field and tailward plasma flows. This study reports the first observations of TRF embedded in a current sheet (possibly diffusion region of magnetic reconnection) in the Martian magnetotail, suggesting the occurrence of RFs without a global dipole magnetic field.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
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
Astronomy & Astrophysics
Honghong Wu, Jiansen He, Shiyong Huang, Liping Yang, Xin Wang, Zhigang Yuan
Summary: The scaling of magnetic fluctuations in solar wind turbulence is important, but the presence of magnetic structures affects the time stationarity of the observed fluctuations. To study the scaling anisotropy, the researchers used a criterion phi < 10 degrees to ensure time stationarity and found that the scaling of the magnetic field is dependent on the order, while the scaling of the velocity field is less significant. The near-Sun solar wind turbulence exhibits different scaling anisotropies compared to near-Earth solar wind turbulence.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Honghong Wu, Shiyong Huang, Xin Wang, Zhigang Yuan, Jiansen He, Liping Yang
Summary: In this study, the influence of intermittent structures on the spectral index and higher-order scaling behavior in near-Sun solar wind turbulence is investigated using magnetic field data measured by Parker Solar Probe. Results show that the multifractal scaling of the magnetic field can be predicted by the log-Poisson intermittency model, and a simple Kolmogorov -5/3 monoscaling recovers after the removal of intermittency. Similar behavior is also found for the scaling of the rotational angle, suggesting the involvement of magnetic discontinuities in the energy transfer process of solar wind turbulence.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Z. Wang, S. Y. Huang, Z. G. Yuan, Y. Y. Wei, K. Jiang, S. B. Xu, J. Zhang, R. T. Lin, L. Yu, Q. Y. Xiong, C. M. Wang
Summary: Using high-resolution data from the Magnetospheric Multiscale mission, this study provides a statistical analysis of electron vortexes in the turbulent terrestrial magnetosheath. The study identifies different magnetic structures where electron vortexes occur, with some structures being known and others unknown. The results show that electron vortexes primarily occur in the subsolar region and have a high occurrence rate. The vortexes are short-lived with an average duration of 1.09 seconds and exhibit ion-scale structures. The analysis of energy dissipation suggests that electron vortexes may play a role in turbulent energy dissipation.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
C. M. Wang, S. Y. Huang, Z. G. Yuan, K. Jiang, J. Zhang, Y. Dong, Q. Y. Xiong
Summary: Using data from the Magnetospheric Multiscale mission, we discovered a double layer within the transition layer of the quasi-perpendicular bow shock. The electric potential generated by this double layer effectively accelerates electrons in the bow shock, as verified by the increase in electron parallel temperature. Additionally, we detected strong whistler emissions near this double layer, suggesting that the accelerated electrons can supply the necessary energy for excitation of the observed whistler waves. Hence, the presence of whistler waves indirectly provides evidence of an electron beam generated by the double layer in the bow shock.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Fouad Sahraoui, Shiyong Huang
Summary: Large surveys have found different slope distributions in the power spectral density of magnetic fluctuations in the solar wind at different scales. This article reviews existing explanations for the broadening of slope at sub-ion scales, and proposes a new explanation based on the relative importance of dispersive effects and Doppler shift. By constructing a toy model, the study shows that variations in the angle and flow speed can reproduce the observed slope distribution at sub-ion scales.
ASTROPHYSICAL JOURNAL
(2023)
Article
Geosciences, Multidisciplinary
S. B. Xu, S. Y. Huang, F. Sahraoui, Z. G. Yuan, H. H. Wu, K. Jiang, J. Zhang, R. T. Lin
Summary: This study performs a statistical survey of the power spectra with the Kolmogorov scaling in Saturn's magnetosphere using Cassini measurements. The results show that both magnetic-field and electron density spectra exhibit f (-5/3) at the MHD scales. The statistical analysis reveals a wide-ranging and abundant presence of Kolmogorov spectra throughout magnetosphere, observed across all local times.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Q. Y. Xiong, S. Y. Huang, Z. G. Yuan, K. Jiang, S. B. Xu, R. T. Lin, L. Yu
Summary: Magnetic reconnection is a fundamental process that converts magnetic energy into particles. The electron diffusion region (EDR) plays a crucial role in this process. In this study, it is revealed through simulations that part of the decelerated electrons in the outer EDR can even move back to the inner EDR, suggesting a magnetic Marangoni effect in space plasma. This finding introduces a novel mechanism in the EDR during magnetic reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
S. B. Xu, S. Y. Huang, Z. G. Yuan, H. H. Wu, K. Jiang, J. Zhang
Summary: This study investigates intermittent structures and intermittent heating in Saturn's magnetosphere based on observations from the Cassini spacecraft. Positive correlations are found between electron temperature and magnetic field intermittency, as well as between turbulence heating rate and the probability density of intermittent structures. These results suggest that intermittent structures contribute to turbulent heating in Saturn's magnetosphere.
GEOPHYSICAL RESEARCH LETTERS
(2023)
