Article
Astronomy & Astrophysics
T. Pitkanen, G. S. Chong, M. Hamrin, A. Kullen, T. Karlsson, J. -S. Park, M. Nowada, S. T. Yao, A. W. Degeling, A. M. Tian, Q. Q. Shi
Summary: In this study, the magnetic forces (magnetic pressure gradient force, curvature force, and their sum j x B-force) associated with earthward bursty bulk flows (BBFs) were investigated using Magnetospheric Multiscale (MMS) data. The results showed that in the 2017-2018 data, BBFs were accelerated earthward by the magnetic pressure gradient force beyond 19 R-E and decelerated closer to that distance. The force magnitudes increased with distance, consistent with previous research. In the 2019-2021 data, the pressure gradient force magnitudes were generally smaller, and no clear distance for acceleration reversal could be determined. Curvature forces indicated earthward acceleration independent of distance in both time periods.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Ghai Siung Chong, A. De Spiegeleer, M. Hamrin, T. Pitkanen, H. Gunell, S. Aizawa
Summary: The occurrence of tailward flows in the magnetotail plasma sheet is closely linked to the dynamics of earthward bursty bulk flows (BBFs). Tailward flows around BBFs (TWABs) may hold unique information on its origin. TWABs have a flow velocity magnitude twice larger than the general tailward flows (GTWs), and their plasma density and temperature are comparable with BBFs.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
L. Q. Zhang, Chi. Wang, L. Dai, W. Baumjohann, A. T. Y. Lui, James L. Burch, Yu V. Khotyaintsev, Y. Ren
Summary: The study found that in the reconnection jet process, the vorticity is stronger when dominated by the kinetic electric field compared to when dominated by the convective electric field.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Multidisciplinary Sciences
L. Q. Zhang, Chi Wang, L. Dai, W. Baumjohann, James L. Burch, Yu Khotyaintsev, J. Y. Wang
Summary: This study investigates the main features of the current sheet frozen in the bursty bulk flow using observations from the Magnetospheric Multiscale Spacecraft (MMS). A new model of the bulk flow (BBF) is proposed based on MMS observations, which explains the motion of the BBF in the plasma sheet and predicts the thermal expansion of the BBF after leaving the reconnection source region.
SCIENTIFIC REPORTS
(2022)
Article
Geosciences, Multidisciplinary
Dong Wei, Malcolm W. Dunlop, Junying Yang, Xiangcheng Dong, Yiqun Yu, Tieyan Wang
Summary: This study investigated the characteristics and responses of the magnetosphere-ionosphere-ground system during the January 7, 2015 storm using a multipoint approach combining space-borne measurements and ground magnetic observations. The results provide direct evidence that intense geomagnetic perturbations are caused by magnetospheric BBFs, leading to localized substorm currents. The intense dB/dt variations are associated with a large-scale, substorm current system, driven by multiple BBFs.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Makar V. Leonenko, Elena E. Grigorenko, Lev M. Zelenyi
Summary: We report the MMS observations of intense spikes of field-aligned current (FAC) resulting from magnetic reconnection at plasma sheet (PS) field lines. These spikes, characterized by electric current density of around 70 nA/m^2, were observed near the magnetic separatrix. The FAC structures deeper within the PS were filamented and consisted of multiple spikes with a thickness of approximately 1-2 electron gyroradii (rho(e)). These structures were found to be carried by unmagnetized thermal and suprathermal electron populations, contributing around 20-80% of the total electron population. Strong nonideal electric fields up to about 100 mV/m were detected in the FAC spike near the magnetic separatrix. These fields were mainly generated by anomalous resistivity, potentially caused by electrostatic fluctuations. As a result, significant energy dissipation up to 1.3 nW/m^3 occurred within the electron-scale FAC structure, leading to a doubling of the electron temperature compared to outside the FAC. MMS observations demonstrate the presence of multiple electron-scale FAC layers/filaments in the outer part of the PS during active X-line intervals, where significant energy exchange between electrons and fields occurs. Additional observations and theoretical studies are needed to investigate the stability and lifetime of these filaments.
Article
Engineering, Aerospace
Boris G. Gavrilov
Summary: This study examines how field-aligned currents influence the dynamics of plasma flows. Despite challenges in studying the phenomena due to scale and time constraints, simultaneous measurements from various regions can reveal the complexity of the effect.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
Yin Xu, Huishan Fu, Jinbin Cao, Chengming Liu, Cecilia Norgren, Zuzheng Chen
Summary: A study using the Magnetospheric Multiscale mission investigated the structure and dynamics of an ADF at electron scale, revealing intense current and electric fields at the front of the ADF.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
M. Leonenko, E. E. Grigorenko, L. M. Zelenyi, H. Malova, A. Yu Malykhin, V. Yu Popov, J. Buechner
Summary: Observations of super thin current sheets in the magnetotail plasma sheet show that the electric current is carried by unmagnetized electrons, similar to the mechanism of ion-scale thin current sheet formation by quasi-adiabatic ions. The low-energy population of magnetized electrons is crucial for maintaining the stability of the super thin current sheets.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
H. Arnold, M. I. Sitnov
Summary: The onset of reconnection in the tail requires the current sheet thickness to be of the order of the ion thermal gyroradius or smaller. However, existing isotropic plasma models cannot explain the formation of such thin sheets at distances where the X-lines are typically observed. In this study, we use a new model of equilibria with weakly anisotropic ion species in particle-in-cell simulations and find thin and long sheets that reproduce observation, due to the substantial modification of the current density.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Zhen Zhang, Fabian Walter, Brian W. McArdell, Tjalling de Haas, Michaela Wenner, Malgorzata Chmiel, Siming He
Summary: Observing and estimating the characteristics of debris flows has long been a challenge. Researchers have found that seismic signals from debris flows can provide quantitative information about their properties through modeling.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Astronomy & Astrophysics
Banafsheh Ferdousi, Joachim Raeder, Eftyhia Zesta, William Cramer, Kyle Murphy
Summary: In-situ measurements in the magnetotail are limited, but can be monitored and interpreted through observations in the ionosphere. Understanding the ionosphere and ground observations requires consideration of the coupling processes between the ionosphere and the magnetosphere.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jiayi Liu, Xudong Sun, Peter W. Schuck, Sarah A. Jaeggli, Brian T. Welsch, Carlos Quintero Noda
Summary: This study investigates the Doppler shift characteristics in the central penumbral light bridge of a solar active region and finds a correlation with the cosine of the magnetic inclination. The observations indicate that a new velocity estimator can better recover the Doppler signal. The findings have important implications for understanding the magnetic structure and flow-driving mechanism of sunspots.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
L. Richard, Yu Khotyaintsev, D. B. Graham, M. Sitnov, O. Le Contel, P-A Lindqvist
Summary: This study reports a short-period flapping event of a thin current sheet observed in the plasma sheet, showing characteristics of a drift-kink mode and the presence of lower hybrid waves associated with gradients of density in the thin current sheet.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Chenwei Fan, Xiaohan Cheng, Lin Xu, Maguang Zhu, Sujuan Ding, Chuanhong Jin, Yunong Xie, Lian-Mao Peng, Zhiyong Zhang
Summary: This study demonstrates a multilayer stackable process for the integration of high-performance carbon nanotube transistors and ICs. The high-quality nanotube layer is prepared through a low-temperature process, resulting in high-performance transistors. The resulting 3D ICs show fast signal propagation and compact size.
Article
Geosciences, Multidisciplinary
Fan Gong, Yiqun Yu, Jinbin Cao, Yong Wei, Jiawei Gao, Hui Li, Binzheng Zhang, Aaron Ridley
Summary: This study simulates the solar wind-magnetosphere interactions during a paleomagnetic reversal and finds that the magnetosphere shrinks, with the subsolar magnetopause approaching as close as 3 Re, and multiple magnetic reconnection sites emerge, allowing the solar wind to directly access the magnetosphere and increasing the power transmission efficiency to 18%.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Xingbin Tian, Yiqun Yu, Minghui Zhu, Longxing Ma, Jinbin Cao, P. R. Shreedevi, Vania K. Jordanova, Stanley C. Solomon
Summary: This study investigates the proton precipitation caused by electromagnetic ion cyclotron waves and its impact on the ionosphere. The results show that the precipitation of energetic protons influences the ionosphere-thermosphere and contributes to ionization in the E/F regions. Additionally, the inclusion of the EMIC wave scattering in the model leads to significant changes in the global distribution of precipitating electron flux.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Milla M. H. Kalliokoski, Emilia K. J. Kilpua, Adnane Osmane, Allison N. Jaynes, Drew L. Turner, Harriet George, Lucile Turc, Minna Palmroth
Summary: Coronal mass ejection driven sheath regions play a key role in outer radiation belt responses, with varying effects on electron populations based on sheath properties. Case studies using Van Allen Probes data showed different impacts of sheaths on outer belt electrons, with significant variation in electron fluxes and different responses observed. Inward and outward radial transport driven by ultra-low frequency waves were found to be important in electron energization and loss, with distinct mechanisms in action during different events.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Joachim Birn, Michael Hesse, Andrei Runov, Drew L. Turner, Ian Cohen, James A. Slavin
Summary: In this study, we used combined MHD and test particle simulations to explore the characteristics of ion acceleration in the tailward region of a near-Earth reconnection site. Our findings indicate that acceleration primarily occurs through simple crossings of the enhanced electric field near the x-line or in the departing plasmoid, with the majority of accelerated ions originating from the dawnward side of the central plasma sheet.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Correction
Astronomy & Astrophysics
Yiqun Yu, Jinbin Cao, Zuyin Pu, Vania K. Jordanova, Aaron Ridley
SPACE SCIENCE REVIEWS
(2023)
Article
Crystallography
Hao Zhang, Zhe Zhu, Zhonghua Yao, Hua Hao, Lingyun Wang, Minghe Cao, Hanxing Liu
Summary: A novel high-performance ternary composition was designed, which displayed typical relaxor characteristics and showed great potential in energy storage fields. The composition achieved optimum energy storage properties at x = 0.35, with energy efficiency of 84.87%, energy storage density of 2.3 J/cm(3), and good temperature stability of less than 10% in the temperature range of 20-160 degrees C. Furthermore, the samples exhibited stable cycling fatigue after 10(5) cycles and a fast discharge time of t(0.9) < 0.1 mu s, indicating promising applications in energy units.
Article
Materials Science, Ceramics
Shihao Qiang, Zhe Zhu, Zhonghua Yao, Hua Hao, Minghe Cao, Hanxing Liu
Summary: The polarization response and defect mechanism of (Ba, Ca)(Zr, Ti)O3 piezoelectric ceramics were extensively studied through doping modification. Aluminum doping led to reduced piezoelectric polarization response but improved fatigue resistance and quality factor, demonstrating acceptor characteristics. The role of defect dipole and oxygen vacancy in improving cyclic fatigue behavior was distinguished using thermally stimulated depolarization currents (TSDC). The formation of oxygen vacancies by aluminum doping was confirmed to contribute to the improvement of fatigue behavior. This study provides a promising method to understand the origin of piezoelectric characteristics based on defect configuration in advanced dielectrics.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Zirui Lin, Zhe Zhu, Zhonghua Yao, Hao Zhang, Hua Hao, Minghe Cao, Hanxing Liu
Summary: The preparation of low-cost multilayer piezoelectric devices requires the use of cheap internal electrodes. One strategy is to reduce the sintering temperature of the ceramic layer by adding sintering aids that can form a liquid phase. In this study, 0.2 wt% Li2CO3 was added as a sintering aid to optimize the sinterability and piezoelectric properties of the PZT ceramics, resulting in high piezoelectric coefficients, planar coupling factors, and low mechanical quality factors.
Article
Crystallography
Jianlu Geng, Dongxu Li, Hua Hao, Qinghu Guo, Huihuang Xu, Minghe Cao, Zhonghua Yao, Hanxing Liu
Summary: A modulating crystalline/amorphous phase structure strategy is proposed to enhance the energy storage performance of BaTiO3 films by Mn-doping and annealing temperature control.
Article
Astronomy & Astrophysics
Yihui Song, Haoyu Lu, Jinbin Cao, Shibang Li, Yiqun Yu, Siqi Wang, Yasong Ge, Xiaoxin Zhang, Chenling Zhou, Jianxuan Wang
Summary: Disturbed solar wind dynamic pressure can have significant impacts on the Martian plasma environment. In this study, a numerical model is used to simulate the interaction between solar wind and Mars, analyzing the effects of electromagnetic forces on different ion species. The results show that electromagnetic forces play a crucial role in decelerating solar wind plasma and compressing heavy ions towards Mars.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Haobo Fu, Chao Yue, Q. -g. Zong, XuZhi Zhou, Yiqun Yu, Yuxuan Li, Jianjun Liu, Zejun Hu, Huigen Yang, Geoffrey D. Reeves, Harlan E. Spence, Andrew J. Gerrard, Matina Gkioulidou, Donald G. Mitchell
Summary: In this study, the effects of substorms on plasma pressure and current system in the inner magnetosphere were investigated based on statistical analysis of Van Allen Probes observations from 2012 to 2019. The results showed a significant increase in plasma pressure during intense substorms, leading to a geomagnetic depression of approximately 3 nT/hr. The contribution of <100 keV H+ ions to plasma pressure increased during substorms, especially at lower L-shells, while >10 keV O+ ions contributed more to plasma pressure as substorm intensity increased. Furthermore, the rise in plasma pressure was mainly observed from dusk to midnight, enhancing the asymmetric ring current and field-aligned currents connecting to the ionosphere in region II.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Materials Science, Ceramics
Xinxing Hao, Zhe Zhu, Zhonghua Yao, Hua Hao, Minghe Cao, Hanxing Liu
Summary: This study investigates the effect of polarization difference on the energy storage density of dielectric materials and finds that excess Ti can optimize the dielectric characteristics. The study also highlights the importance of polarization difference in achieving high energy storage density in electrostatic dielectric capacitors.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Qinghu Guo, Dongxu Li, Zhonghua Yao, Huajun Sun, Hua Hao, Hanxing Liu, Shujun Zhang
Summary: This study reports the design of a critical phase point where reversible transition from the ergodic relaxor state to an unstable long-range ordered ferroelectric state takes place, achieving high electrostrictive strain. By introducing a strong relaxor component and designing a morphotropic relaxor phase boundary, the performance of the material has been significantly improved.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Geochemistry & Geophysics
Huang HongTao, Yu YiQun
Summary: Using particle-in-cell simulations, this study investigates the energy conversion and energy partition at the dipolarization front. It is found that the ion energy gain is 90% of the released magnetic energy while the electron energy gain is 10% of it. Introducing a moderate guide field increases the ion energy gain to 95% of the released energy, while reducing the electron energy gain to 5% of it.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2022)
Article
Geosciences, Multidisciplinary
MingHui Zhu, YiQun Yu, Xing Cao, BinBin Ni, XingBin Tian, JinBin Cao, Vania K. Jordanova
Summary: This study investigates the effects of polarization-reversed EMIC waves on the dynamics of the ring current and proton precipitation loss. The results show that the polarization reversal can decrease the scattering rates of protons and slightly affect the global ring current intensity and proton precipitation.
EARTH AND PLANETARY PHYSICS
(2022)