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2. A comparison of methods for finding magnetic nulls in simulations and in situ observations of space plasmas

Author

Olshevsky, Vyacheslav, Pontin, David, Williams, Benjamin, Parnell, Clare, Fu, Huishan, Liu, Yangyang, Yao, Shutao, and Khotyaintsev, Yuri

Subjects
Physics - Space Physics, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics
Abstract

Magnetic nulls are ubiquitous in space plasmas, and are of interest as sites of localized energy dissipation or magnetic reconnection. As such, a number of methods have been proposed for detecting nulls in both simulation data and in situ spacecraft data from Earth's magnetosphere. The same methods can be applied to detect stagnation points in flow fields. In this paper we describe a systematic comparison of different methods for finding magnetic nulls. The Poincare index method, the first-order Taylor expansion (FOTE) method, and the trilinear method are considered. We define a magnetic field containing fourteen magnetic nulls whose positions and types are known to arbitrary precision. Furthermore, we applied the selected techniques in order to find and classify those nulls. Two situations are considered: one in which the magnetic field is discretized on a rectangular grid, and the second in which the magnetic field is discretized along synthetic `spacecraft trajectories' within the domain. At present, FOTE and trilinear are the most reliable methods for finding nulls in the spacecraft data and in numerical simulations on Cartesian grids, respectively. The Poincare index method is suitable for simulations on both tetrahedral and hexahedral meshes. The proposed magnetic field configuration can be used for grading and benchmarking the new and existing tools for finding magnetic nulls and flow stagnation points., Comment: Reproduced with permission from Astronomy & Astrophysics, \c{opyright} ESO

Published
2020
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4. Particle Energization in Space Plasmas: Towards a Multi-Point, Multi-Scale Plasma Observatory. A White Paper for the Voyage 2050 long-term plan in the ESA's Science Programme

Author

Retino, Alessandro, Khotyaintsev, Yuri, Contel, Olivier Le, Marcucci, Maria Federica, Plaschke, Ferdinand, Vaivads, Andris, Angelopoulos, Vassilis, Blasi, Pasquale, De Keyser, Jim Burch Johan, Dunlop, Malcolm, Dai, Lei, Eastwood, Jonathan, Fu, Huishan, Haaland, Stein, Hoshino, Masahiro, Johlander, Andreas, Kepko, Larry, Kucharek, Harald, Lapenta, Gianni, Lavraud, Benoit, Malandraki, Olga, Matthaeus, William, McWilliams, Kathryn, Petrukovich, Anatoli, Pinçon, Jean-Louis, Saito, Yoshifumi, Sorriso-Valvo, Luca, Vainio, Rami, and Wimmer-Schweingruber, Bob

Subjects
Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics, Physics - Plasma Physics
Abstract

This White Paper outlines the importance of addressing the fundamental science theme <> through a future ESA mission. The White Paper presents five compelling science questions related to particle energization by shocks, reconnection,waves and turbulence, jets and their combinations. Answering these questions requires resolving scale coupling, nonlinearity and nonstationarity, which cannot be done with existing multi-point observations. In situ measurements from a multi-point, multi-scale L-class plasma observatory consisting of at least 7 spacecraft covering fluid, ion and electron scales are needed. The plasma observatory will enable a paradigm shift in our comprehension of particle energization and space plasma physics in general, with very important impact on solar and astrophysical plasmas. It will be the next logical step following Cluster, THEMIS and MMS for the very large and active European space plasmas community. Being one of the cornerstone missions of the future ESA Voyage 2035-2050 science program, it would further strengthen the European scientific and technical leadership in this important field.

Published
2019

5. In situ spacecraft observations of a structured electron diffusion region during magnetopause reconnection

Author

Cozzani, Giulia, Retinò, Alessandro, Califano, Francesco, Alexandrova, Alexandra, Contel, Olivier Le, Khotyaintsev, Yuri, Vaivads, Andris, Fu, Huishan, Catapano, Filomena, Breuillard, Hugo, Ahmadi, Narges, Lindqvist, Per-Arne, Ergun, Robert E., Torbert, Robert B., Giles, Barbara L., Russell, Christopher T., Nakamura, Rumi, Fuselier, Stephen, Mauk, Barry H., Moore, Thomas, and Burch, James L.

Subjects
Physics - Plasma Physics
Abstract

The Electron Diffusion Region (EDR) is the region where magnetic reconnection is initiated and electrons are energized. Because of experimental difficulties, the structure of the EDR is still poorly understood. A key question is whether the EDR has a homogeneous or patchy structure. Here we report Magnetospheric MultiScale (MMS) novel spacecraft observations providing evidence of inhomogeneous current densities and energy conversion over a few electron inertial lengths within an EDR at the terrestrial magnetopause, suggesting that the EDR can be rather structured. These inhomogenenities are revealed through multi-point measurements because the spacecraft separation is comparable to a few electron inertial lengths, allowing the entire MMS tetrahedron to be within the EDR most of the time. These observations are consistent with recent high-resolution and low-noise kinetic simulations.

Published
2019
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6. Particle energization in space plasmas: towards a multi-point, multi-scale plasma observatory

Author

Retinò, Alessandro, Khotyaintsev, Yuri, Le Contel, Olivier, Marcucci, Maria Federica, Plaschke, Ferdinand, Vaivads, Andris, Angelopoulos, Vassilis, Blasi, Pasquale, Burch, Jim, De Keyser, Johan, Dunlop, Malcolm, Dai, Lei, Eastwood, Jonathan, Fu, Huishan, Haaland, Stein, Hoshino, Masahiro, Johlander, Andreas, Kepko, Larry, Kucharek, Harald, Lapenta, Gianni, Lavraud, Benoit, Malandraki, Olga, Matthaeus, William, McWilliams, Kathryn, Petrukovich, Anatoli, Pinçon, Jean-Louis, Saito, Yoshifumi, Sorriso-Valvo, Luca, Vainio, Rami, and Wimmer-Schweingruber, Robert

Published
2022
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7. Excitation of Low‐ and High‐Frequency Magnetosonic Whistler Waves Associated With SLAMS in the Terrestrial Foreshock.

Author

Yao, Yuhang, Zhao, Jinsong, Fu, Huishan, Lin, Yu, Zhang, Wenzhe, Wang, Tieyan, Dong, Xiangcheng, Dunlop, Malcolm W., Wu, Dejin, and Guo, Xudong

Subjects
PLASMA waves, MAGNETIC structure, PARTICLE dynamics, RELATIVE velocity, ELECTRON distribution
Abstract

Based on observations from the Magnetospheric Multiscale mission, this study presents an analysis of a short large‐amplitude magnetic structures (SLAMS) event with simultaneous occurrence of low‐ and high‐frequency magnetosonic whistler waves. It was found that low‐frequency magnetosonic whistler waves around the lower‐hybrid frequency emerge in the presence of solar wind ions and local low‐energy ions in the trailing region of SLAMS. Additionally, counter‐propagating whistler waves (the high‐frequency branch of the magnetosonic whistler wave) are observed within SLAMS, coinciding with a perpendicular temperature anisotropy in the electron population. Instability analyses demonstrate that these low‐frequency waves are induced by the two‐stream instability associated with the cross‐field relative velocity between low‐energy ions and electrons, while whistler waves are locally generated by the whistler anisotropy instability. Our results shed light on the impact of SLAMS on particle and wave dynamics in the terrestrial foreshock. Plain Language Summary: Short large‐amplitude magnetic structures (SLAMS) are frequently observed within the terrestrial foreshock. They play a significant role in particle dynamics, often leading to the formation of unstable ion and electron velocity distributions. Consequently, plasma waves are excited across both ion and electron scales. Despite their importance, direct observational evidence linking SLAMS to the local excitation of plasma waves has been lacking. In this study, we utilized observations from the Magnetospheric Multiscale mission to investigate the local excitation of magnetosonic whistler waves associated with SLAMS. We revealed the presence of counter‐propagating whistler waves within SLAMS. We attributed the generation of these waves to the local whistler anisotropy instability. Furthermore, we found the occurrence of low‐frequency magnetosonic whistler waves in the trailing region of SLAMS. We identified their excitation mechanism as the two‐stream instability relating to local low‐energy ions. These results offer valuable insights into the intricate interplay between SLAMS and particle‐wave dynamics within the terrestrial foreshock. Key Points: MMS observes both low‐ and high‐frequency magnetosonic whistler waves associated with SLAMS in Earth's foreshockCounter‐propagating high‐frequency magnetosonic whistler waves are proposed to be excited by the whistler anisotropy instability in SLAMSLow‐frequency magnetosonic whistler waves are excited by the cross‐field relative velocity between low‐energy reflected ions and electrons [ABSTRACT FROM AUTHOR]

Published
2024
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13. Curlometer technique and applications

Author

Dong, Xiangcheng, primary, Dunlop, Malcolm, additional, Shen, Chao, additional, Wang, Tieyan, additional, Robert, Patrick, additional, Eastwood, Jonathan, additional, Haaland, Stein, additional, Yang, Yanyan, additional, Tan, Xin, additional, Escoubet, Philippe, additional, Rong, Zhaojin, additional, Fu, Huishan, additional, and De Keyser, Johan, additional

Published
2023
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14. A Large‐Scale Magnetospheric Line Radiation Event in the Upper Ionosphere Recorded by the China‐Seismo‐Electromagnetic Satellite

Author

Hu, Yunpeng, primary, Zhima, Zeren, additional, Fu, Huishan, additional, Cao, Jinbin, additional, Piersanti, Mirko, additional, Wang, Tieyan, additional, Yang, Dehe, additional, Sun, Xiaoying, additional, Lv, Fangxian, additional, Lu, Chao, additional, Wang, Qiao, additional, Wang, Yalu, additional, and Shen, Xuhui, additional

Published
2023
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15. Strategic Study for the Development of Space Physics

Author

WANG, Chi, primary, WANG, Yuming, additional, TIAN, Hui, additional, LI, Hui, additional, NI, Binbin, additional, FU, Huishan, additional, LEI, Jiuhou, additional, XUE, Xianghui, additional, CUI, Jun, additional, YAO, Zhonghua, additional, LUO, Bingxian, additional, ZHANG, Xiaoxin, additional, ZHANG, Aibing, additional, ZHANG, Jiaojiao, additional, and LI, Wenya, additional

Published
2023
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20. Particle energization in space plasmas: towards a multi-point, multi-scale plasma observatory

Author

Retinò, Alessandro, primary, Khotyaintsev, Yuri, additional, Le Contel, Olivier, additional, Marcucci, Maria Federica, additional, Plaschke, Ferdinand, additional, Vaivads, Andris, additional, Angelopoulos, Vassilis, additional, Blasi, Pasquale, additional, Burch, Jim, additional, De Keyser, Johan, additional, Dunlop, Malcolm, additional, Dai, Lei, additional, Eastwood, Jonathan, additional, Fu, Huishan, additional, Haaland, Stein, additional, Hoshino, Masahiro, additional, Johlander, Andreas, additional, Kepko, Larry, additional, Kucharek, Harald, additional, Lapenta, Gianni, additional, Lavraud, Benoit, additional, Malandraki, Olga, additional, Matthaeus, William, additional, McWilliams, Kathryn, additional, Petrukovich, Anatoli, additional, Pinçon, Jean-Louis, additional, Saito, Yoshifumi, additional, Sorriso-Valvo, Luca, additional, Vainio, Rami, additional, and Wimmer-Schweingruber, Robert, additional

Published
2021
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22. In situ spacecraft observations of structured electron diffusion regions during magnetic reconnection

Author

Cozzani, Giulia, Retinò, Alessandro, Califano, Francesco, Alexandrova, Alexandra, Khotyaintsev, Yuri, André, Mats, Catapano, Filomena, Fu, Huishan, Le Contel, Olivier, Vaivads, Andris, Ahmadi, Narges, Breuillard, Hugo, Swedish Institute of Space Physics [Uppsala] (IRF), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica dell'Universita di Pisa and INFN,Pisa, University of Pisa - Università di Pisa, Department of Earth Observation Future Missions, European Space Research Institute (ESRIN), European Space Agency (ESA)-European Space Agency (ESA), Beihang University (BUAA), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), and University of Colorado [Boulder]

Subjects
[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Physics::Space Physics, 7. Clean energy
Abstract

Magnetic reconnection is a fundamental energy conversion process in plasmas. It occurs in thin current sheets, where a change in the magnetic field topology leads to rapid heating of plasma, plasma bulk acceleration and acceleration of plasma particles. To allow for magnetic field reconfiguration, both ions and electrons must be demagnetized. The ion and electron demagnetization take place in the ion and electron diffusion regions respectively, in both cases at kinetic scales. For the first time, Magnetospheric Multiscale (MMS) spacecraft observations, at inter-spacecraft separation comparable to the electron inertial length, allow for a multi-point analysis of the electron diffusion region (EDR). A key question is whether the EDR has a homogeneous or patchy structure. Here we report MMS observations at the magnetopause providing evidence of inhomogeneous current densities and energy conversion over a few (∼ 3 de) electron inertial lengths suggesting that the EDR can be structured at electron scales. In particular, the energy conversion is patchy and changing sign in the vicinity of the reconnection site implying that the EDR comprises regions where energy is transferred from the field to the plasma and regions with the opposite energy transition, which is unexpected during reconnection. The origin of the patchy energy conversion appears to be connected to the large ve,N ∼ ve,M directed from the magnetosphere to magnetosheath. These observations are consistent with recent high-resolution and low-noise kinetic simulations of asymmetric reconnection. Patchy energy conversion is observed also in an EDR at the magnetotail, where the inter-spacecraft separation was ∼ 1 de. Electric field measurements are different among the spacecraft suggesting inhomogeneities at the electron scale. However, in this case the current density appear homogeneous in the EDR suggesting that the structuring may be sourced from a different kind of electron dynamics in the magnetotail.

Published
2020
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24. Solar wind - magnetosphere coupling during radial IMF conditions: simultaneous multi-point observations

Author

Toledo-Redondo, Sergio, primary, Hwang, Kyoung-Joo, additional, Escoubet, Christopher Philippe, additional, Lavraud, Benoit, additional, Fornieles, Jesús, additional, Aunai, Nicolas, additional, Fear, Robert C, additional, Dargent, Jérémy, additional, Fu, Huishan, additional, Fuselier, Stephen A., additional, Genestreti, Kevin J, additional, Khotyaintsev, Yuri V., additional, Li, Wenya, additional, Norgren, Cecilia, additional, and Phan, Tai-Duc, additional

Published
2021
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25. Multispacecraft Measurements in the Magnetosphere

Author

Dunlop, Malcolm W., primary, Wang, TieYan, additional, Dong, XiangCheng, additional, Haarland, Stein, additional, Shi, QuanQi, additional, Fu, HuiShan, additional, Keyser, Johan, additional, Shen, Chao, additional, Rong, ZhaoJin, additional, Escoubet, Christophe Phillippe, additional, Pu, ZuYin, additional, and Eastwood, Jonathan, additional

Published
2021
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27. Kinetic interaction of cold and hot protons with an oblique EMIC wave near the dayside reconnecting magnetopause

Author

Toledo-Redondo, Sergio, primary, Lee, Justin H., additional, Vines, Sarah K., additional, Turner, Drew L., additional, Allen, Robert C., additional, André, Mats, additional, Boardsen, Scott A., additional, Burch, James L., additional, Denton, Richard E., additional, Fu, Huishan, additional, Fuselier, Stephen A., additional, Giles, Barbara, additional, Kitamura, Naritoshi, additional, Khotyaintsev, Yuri V., additional, Lavraud, Benoit, additional, LeContel, Olivier, additional, Li, Wenya, additional, Navarro, Enrique A., additional, Portí, Jorge, additional, and Salinas, Alfonso, additional

Published
2021
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29. In Situ Detection of the Solar Eruption: Lay a Finger on the Sun

Author

LIN, Jun, primary, HUANG, Shanjie, additional, LI, Yan, additional, CHONG, Xiaoyu, additional, ZHANG, Shenyi, additional, LI, Mingtao, additional, ZHANG, Yiteng, additional, ZHOU, Bin, additional, OUYANG, Gaoxiang, additional, XIANG, Lei, additional, DONG, Liang, additional, JI, Haisheng, additional, TIAN, Hui, additional, SONG, Hongqiang, additional, LIU, Yu, additional, JIN, Zhenyu, additional, FENG, Jing, additional, ZHANG, Hongbo, additional, ZHANG, Xianguo, additional, ZHANG, Weijie, additional, HUANG, Min, additional, LÜ, Qunbo, additional, DENG, Lei, additional, FU, Huishan, additional, CHENG, Xin, additional, and WANG, Min, additional

Published
2021
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30. AME: A Cross-Scale Constellation of CubeSats to Explore Magnetic Reconnection in the Solar–Terrestrial Relation

Author

Dai, Lei, primary, Wang, Chi, additional, Cai, Zhiming, additional, Gonzalez, Walter, additional, Hesse, Michael, additional, Escoubet, Philippe, additional, Phan, Tai, additional, Vasyliunas, Vytenis, additional, Lu, Quanming, additional, Li, Lei, additional, Kong, Linggao, additional, Dunlop, Malcolm, additional, Nakamura, Rumi, additional, He, Jianshen, additional, Fu, Huishan, additional, Zhou, Meng, additional, Huang, Shiyong, additional, Wang, Rongsheng, additional, Khotyaintsev, Yuri, additional, Graham, Daniel, additional, Retino, Alessandro, additional, Zelenyi, Lev, additional, Grigorenko, Elena E., additional, Runov, Andrei, additional, Angelopoulos, Vassilis, additional, Kepko, Larry, additional, Hwang, Kyoung-Joo, additional, and Zhang, Yongcun, additional

Published
2020
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35. AME : A Cross-Scale Constellation of CubeSats to Explore Magnetic Reconnection in the Solar-Terrestrial Relation

Author

Dai, Lei, Wang, Chi, Cai, Zhiming, Gonzalez, Walter, Hesse, Michael, Escoubet, Philippe, Phan, Tai, Vasyliunas, Vytenis, Lu, Quanming, Li, Lei, Kong, Linggao, Dunlopla, Malcolm, Nakamura, Rumi, He, Jianshen, Fu, Huishan, Zhou, Meng, Huang, Shiyong, Wang, Rongsheng, Khotyaintsev, Yuri V., Graham, Daniel, Retino, Alessandro, Zelenyi, Lev, Grigorenko, Elena E., Runov, Andrei, Angelopoulos, Vassilis, Kepko, Larry, Hwang, Kyoung-Joo, Zhang, Yongcun, Dai, Lei, Wang, Chi, Cai, Zhiming, Gonzalez, Walter, Hesse, Michael, Escoubet, Philippe, Phan, Tai, Vasyliunas, Vytenis, Lu, Quanming, Li, Lei, Kong, Linggao, Dunlopla, Malcolm, Nakamura, Rumi, He, Jianshen, Fu, Huishan, Zhou, Meng, Huang, Shiyong, Wang, Rongsheng, Khotyaintsev, Yuri V., Graham, Daniel, Retino, Alessandro, Zelenyi, Lev, Grigorenko, Elena E., Runov, Andrei, Angelopoulos, Vassilis, Kepko, Larry, Hwang, Kyoung-Joo, and Zhang, Yongcun

Abstract

A major subset of solar-terrestrial relations, responsible, in particular, for the driver of space weather phenomena, is the interaction between the Earth's magnetosphere and the solar wind. As one of the most important modes of the solar-wind-magnetosphere interaction, magnetic reconnection regulates the energy transport and energy release in the solar-terrestrial relation. In situ measurements in the near-Earth space are crucial for understanding magnetic reconnection. Past and existing spacecraft constellation missions mainly focus on the measurement of reconnection on plasma kinetic-scales. Resolving the macro-scale and cross-scale aspects of magnetic reconnection is necessary for accurate assessment and predictions of its role in the context of space weather. Here, we propose the AME (self-Adaptive Magnetic reconnection Explorer) mission consisting of a cross-scale constellation of 12+ CubeSats and one mother satellite. Each CubeSat is equipped with instruments to measure magnetic fields and thermal plasma particles. With multiple CubeSats, the AME constellation is intended to make simultaneous measurements at multiple scales, capable of exploring cross-scale plasma processes ranging from kinetic scale to macro scale.

Published
2020
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36. In Situ Detection of the Solar Eruption: Lay a Finger on the Sunormalsize

Author

null LIN Jun, null HUANG Shanjie, null LI Yan, null CHONG Xiaoyu, null ZHANG Shenyi, null LI Mingtao, null ZHANG Yiteng, null ZHOU Bin, null OUYANG Gaoxiang, null XIANG Lei, null DONG Liang, null JI Haisheng, null TIAN Hui, null SONG Hongqiang, null LIU Yu, null JIN Zhenyu, null FENG Jing, null ZHANG Hongbo, null ZHANG Xianguo, null ZHANG Weijie, null HUANG Min, null LÜ Qunbo, null DENG Lei, null FU Huishan, null CHENG Xin, and null WANG Min

Subjects
Complementary and alternative medicine, Pharmaceutical Science, Pharmacology (medical)
Published
2021
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38. A new method to identify flux ropes in space plasmas

Author

Huang, Shiyong, primary, Zhao, Pufan, additional, He, Jiansen, additional, Yuan, Zhigang, additional, Zhou, Meng, additional, Fu, Huishan, additional, Deng, Xiaohua, additional, Pang, Ye, additional, Wang, Dedong, additional, Yu, Xiongdong, additional, Li, Haimeng, additional, Torbert, Roy, additional, and Burch, James, additional

Published
2018
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40. Statistical correlation analysis of field-aligned currents measured by Swarm

Author

Yang, Junying, Dunlop, Malcolm G, Lühr, H., Xiong, Chao, Yang, Yanyan, Cao, Jin Bin, Wild, James Anderson, Li, L. Y., Ma, Yuduan, Liu, Wenlong, Fu, Huishan, Lu, Haoyu, Waters, Colin, Ritter, Patricia, Yang, Junying, Dunlop, Malcolm G, Lühr, H., Xiong, Chao, Yang, Yanyan, Cao, Jin Bin, Wild, James Anderson, Li, L. Y., Ma, Yuduan, Liu, Wenlong, Fu, Huishan, Lu, Haoyu, Waters, Colin, and Ritter, Patricia

Published
2018

44. Statistical properties of kinetic‐scale magnetic holes in terrestrial space

Author

Yao, ShuTao, Yue, ZongShun, Shi, QuanQi, Degeling, Alexander William, Fu, HuiShan, Tian, AnMin, Zhang, Hui, Vu, Andrew, Guo, RuiLong, Yao, ZhongHua, Liu, Ji, Zong, Qiu‐Gang, Zhou, XuZhi, Li, JingHuan, Li, WenYa, Hu, HongQiao, Liu, YangYang, and Sun, WeiJie

Abstract

Kinetic‐scale magnetic holes (KSMHs) are structures characterized by a significant magnetic depression with a length scale on the order of the proton gyroradius. These structures have been investigated in recent studies in near‐Earth space, and found to be closely related to energy conversion and particle acceleration, wave‐particle interactions, magnetic reconnection, and turbulence at the kinetic‐scale. However, there are still several major issues of the KSMHs that need further study — including (a) the source of these structures (locally generated in near‐Earth space, or carried by the solar wind), (b) the environmental conditions leading to their generation, and (c) their spatio‐temporal characteristics. In this study, KSMHs in near‐Earth space are investigated statistically using data from the Magnetospheric Multiscale mission. Approximately 200,000 events were observed from September 2015 to March 2020. Occurrence rates of such structures in the solar wind, magnetosheath, and magnetotail were obtained. We find that KSMHs occur in the magnetosheath at rates far above their occurrence in the solar wind. This indicates that most of the structures are generated locally in the magnetosheath, rather than advected with the solar wind. Moreover, KSMHs occur in the downstream region of the quasi‐parallel shock at rates significantly higher than in the downstream region of the quasi‐perpendicular shock, indicating a relationship with the turbulent plasma environment. Close to the magnetopause, we find that the depths of KSMHs decrease as their temporal‐scale increases. We also find that the spatial‐scales of the KSMHs near the subsolar magnetosheath are smaller than those in the flanks. Furthermore, their global distribution shows a significant dawn‐dusk asymmetry (duskside dominating) in the magnetotail. Most KSMHs are locally generated in the magnetosheath, rather than advected with the solar wind.KSMHs are more likely to be generated downstream of the quasi‐parallel shock, indicating the importance of turbulence in their generation.The scale‐size of KSMHs is smaller near the subsolar magnetosheath than along the flanks, indicating they may be affected by the magnetosheath pressure environment. Most KSMHs are locally generated in the magnetosheath, rather than advected with the solar wind. KSMHs are more likely to be generated downstream of the quasi‐parallel shock, indicating the importance of turbulence in their generation. The scale‐size of KSMHs is smaller near the subsolar magnetosheath than along the flanks, indicating they may be affected by the magnetosheath pressure environment.

Published
2021
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45. On the calculation of electric diffusion coefficient of radiation belt electrons with in situ electric field measurements by THEMIS

Author

Liu, Wenlong, Tu, Weichao, Li, Xinlin, Sarris, Theodore, Khotyaintsev, Yuri, Fu, Huishan, Zhang, Hui, Shi, Quanqi, Liu, Wenlong, Tu, Weichao, Li, Xinlin, Sarris, Theodore, Khotyaintsev, Yuri, Fu, Huishan, Zhang, Hui, and Shi, Quanqi

Abstract

Based on 7years' observations from Time History of Events and Macroscale Interactions during Substorms (THEMIS), we investigate the statistical distribution of electric field Pc5 ULF wave power under different geomagnetic activities and calculate the radial diffusion coefficient due to electric field, , for outer radiation belt electrons. A simple empirical expression of is also derived. Subsequently, we compare to previous D-LL models and find similar Kp dependence with the model, which is also based on in situ electric field measurements. The absolute value of is constantly higher than , probably due to the limited orbital coverage of CRRES. The differences between and the commonly used and models are significant, especially in Kp dependence and energy dependence. Possible reasons for these differences and their implications are discussed. The diffusion coefficient provided in this paper, which also has energy dependence, will be an important contributor to quantify the radial diffusion process of radiation belt electrons.

Published
2016
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50. Different types of whistler mode chorus in the equatorial source region

Author

Taubenschuss, Ulrich, Santolik, Ondrej, Graham, Daniel B., Fu, Huishan, Khotyaintsev, Yuri V., Le Contel, Olivier, Taubenschuss, Ulrich, Santolik, Ondrej, Graham, Daniel B., Fu, Huishan, Khotyaintsev, Yuri V., and Le Contel, Olivier

Abstract

The Time History of Events and Macroscale Interactions during Substorms-D spacecraft crossed an active equatorial source region of whistler mode chorus rising tones on 23 October 2008. Rising tones are analyzed in terms of spectral and polarization characteristics, with special emphasis on wave normal angles. The latter exhibit large variations from quasi-parallel to oblique, even within single bursts, but seem to follow a definite pattern, which enables an unambiguous classification into five different groups. Furthermore, we discuss the frequently observed splitting of chorus bursts into a lower and an upper band around one half of the local electron cyclotron frequency. At chorus frequencies close to the gap, we find significantly lowered wave planarities and a tendency of wave normal angles to approach the Gendrin angle.

Published
2015
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