Article
Geosciences, Multidisciplinary
Hyangpyo Kim, Kazuo Shiokawa, Jaeheung Park, Yoshizumi Miyoshi, Yukinaga Miyashita, Claudia Stolle, Hyunju Kim Connor, Junga Hwang, Stephan Buchert, Hyuck-Jin Kwon, Satoko Nakamura, Kohki Nakamura, Shin-Ichiro Oyama, Yuichi Otsuka, Tsutomu Nagatsuma, Kaori Sakaguchi
Summary: This study reports concurrent observations of F-region plasma changes and field-aligned currents (FACs) above isolated proton auroras (IPAs), revealing that wave-induced proton precipitation contributes to the energy transfer from the magnetosphere to the ionosphere.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Veronika S. Grach, Anton Artemyev, Andrei G. Demekhov, Xiao-Jia Zhang, Jacob Bortnik, Vassilis Angelopoulos, Rumi Nakamura, Ethan Tsai, Colin Wilkins, Owen W. Roberts
Summary: This study investigates the transport effects of intense electromagnetic ion cyclotron (EMIC) waves on relativistic electron precipitation. Despite the transport of low pitch-angle electrons away from the loss cone, scattering at higher pitch angles results in the loss cone filling and electron precipitation.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Huayue Chen, Xinliang Gao, Quanming Lu, Bruce T. Tsurutani
Summary: This study investigates the distribution and dependences of relativistic electron precipitation (REP) in the Earth's magnetosphere using relativistic electron data. The results show that REP events preferentially occur in MLT = 17-03 at L = 4-6.5, and are correlated with both AE and P-d indices. Possible mechanisms of REP loss are discussed based on the findings.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
Jacob Bortnik, Jay M. Albert, Anton Artemyev, Wen Li, Chae-Woo Jun, Veronika S. Grach, Andrei G. Demekhov
Summary: Recent work has found that EMIC waves occur in four distinct regions, each with their own characteristics and morphology. Nonlinear test-particle simulations were used to study the range of energetic electron scattering responses to two groups of EMIC waves occurring at low L-shells and overlapping with outer radiation belt electrons. The results show that high-density EMIC waves can drive a range of linear and nonlinear behaviors, contradicting conventional expectations and potentially having profound implications for observational campaigns.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
S. Nakamura, Y. Miyoshi, K. Shiokawa, Y. Omura, T. Mitani, T. Takashima, N. Higashio, I Shinohara, T. Hori, S. Imajo, A. Matsuoka, F. Tsuchiya, A. Kumamoto, Y. Kasahara, M. Shoji, H. Spence, V Angelopoulos
Summary: The study observed rapid flux depressions in relativistic electrons, known as EMIC-induced drifting electron holes (EDEHs), caused by electromagnetic ion cyclotron waves on a short timescale in a limited region. These flux depressions occur in the relativistic energy range and small pitch angles, potentially leading to significant depression of the radiation belt.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
L. Capannolo, W. Li, H. Spence, A. T. Johnson, M. Shumko, J. Sample, D. Klumpar
Summary: By analyzing coordinated multisatellite observations, this study found that electron precipitation driven by EMIC waves occurs in a broad region near dusk, mostly confined to 3.5-7.5 L-shells, with each precipitation event occurring on localized radial scales. The data from FIREBIRD-II suggest that EMIC waves can efficiently scatter electron energies from around 200 to 300 keV up to the expected MeV energies.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
A. Bruno, L. W. Blum, G. A. de Nolfo, R. Kataoka, S. Torii, A. D. Greeley, S. G. Kanekal, A. W. Ficklin, T. G. Guzik, S. Nakahira
Summary: This study analyzes the relativistic electron precipitation event measured by the CALET experiment on the International Space Station. The analysis reveals that the electron precipitation is associated with the dusk-side electromagnetic ion cyclotron waves. The findings suggest that the reported radiation belt depletion can be attributed to the effects of EMIC wave scattering driving the atmospheric precipitation and outward radial diffusion associated with magnetopause shadowing.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Sung-Jun Noh, Hyomin Kim, Marc Lessard, Mark Engebretson, Vyacheslav Pilipenko, Eun-Hwa Kim, Jay Johnson, Ilya Kuzichev, Michelle Salzano
Summary: In this study, we investigated the characteristics of EMIC wave propagation and filtering from the source region to the ground. The study utilized magnetometers aboard GOES 13 and the SNK station in northern Canada to obtain simultaneous observations. The results revealed differences in wave properties and environmental factors between coincident and non-coincident wave events.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
A. T. Hendry, A. Seppala, C. J. Rodger, M. A. Clilverd
Summary: The study suggests that electromagnetic ion cyclotron (EMIC) waves can drive energetic electron precipitation (EEP) at unexpectedly low energies, impacting both radiation belt dynamics and the chemical balance of the Earth's atmosphere. The research shows that the impact of EMIC-driven EEP on trapped radiation belt fluxes is not mutually exclusive with previous findings regarding trapped flux populations. Moreover, it highlights the significant ionization of the Earth's atmosphere and potential loss of mesospheric ozone due to EMIC-driven EEP.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Dan Deng, Zhigang Yuan, Zuxiang Xue, Shiyong Huang, Zheng Huang, Xiongdong Yu
Summary: This letter provides the first observational evidence of wave-wave coupling between H+ band and He+ band EMIC waves, using observations from the Van Allen Probes.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Physics, Multidisciplinary
Xin An, Anton Artemyev, Vassilis Angelopoulos, Xiaojia Zhang, Didier Mourenas, Jacob Bortnik
Summary: This study demonstrates that short wave packets can cause nonresonant scattering and explains the occurrence of simultaneous precipitation of hundreds of keV and >1 MeV electrons.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Hyomin Kim, Quintin Schiller, Mark J. Engebretson, Sungjun Noh, Ilya Kuzichev, Louis J. Lanzerotti, Andrew J. Gerrard, Khan-Hyuk Kim, Marc R. Lessard, Harlan E. Spence, Dae-Young Lee, Juergen Matzka, Tanja Fromm
Summary: Observations of electromagnetic ion cyclotron (EMIC) waves and their interactions with high energy particles were conducted using the twin Van Allen Probes spacecraft. Analysis of particle data and ground-based magnetometer observations showed a significant energy-dependent relativistic electron dropout over a limited L-shell range during and after the EMIC wave activity. NOAA spacecraft also observed relativistic electron precipitation associated with the EMIC waves near the footprint of Van Allen Probes.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Lunjin Chen, Xiao-Jia Zhang, Anton Artemyev, Vassilis Angelopoulos, Ethan Tsai, Colin Wilkins, Richard B. Horne
Summary: During magnetospheric storms, energetic electron microbursts are observed. It is found that these microbursts may be caused by ducted whistler-mode lower-band chorus waves.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Ethan Tsai, Anton Artemyev, Xiao-Jia Zhang, Vassilis Angelopoulos
Summary: This study provides evidence for the nonlinear resonant interaction between whistler-mode waves and electron distributions through the detection of high-resolution electron energy and pitch angle spectra, as well as conjugate measurements of equatorial plasma parameters, wave properties, and electron energy spectra. By comparing simulations with observations, the study shows that the observed spectra match the expected values, indicating the importance of nonlinear resonant effects in describing intense precipitation patterns of energetic electrons.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
S. Teng, Q. Ma, X. Tao
Summary: By analyzing data from the Van Allen Probes, researchers have determined the global distribution of simultaneous occurrence of Magnetosonic (MS) and Electromagnetic ion cyclotron (EMIC) waves in the magnetosphere. Their study also quantitatively analyzes the combined effects of these waves on protons and electrons, showing the importance of high-frequency EMIC waves and intense MS waves for proton acceleration and electron loss. This research provides new insights into understanding the distribution of MS and EMIC waves and evaluating their combined effects on energetic particles.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Xiongdong Yu, Zhigang Yuan, Fei Yao, Zhihai Ouyang, Dedong Wang
Summary: This study reports the electromagnetic characteristics of magnetosonic waves in various plasma environments observed by the Van Allen Probe A, finding that a considerable number of observed waves consist of dominated electrostatic components. The comparison between statistical and theoretical analysis shows that the observed waves can be well predicted by cold plasma theory. The validation of cold plasma approximation to estimate the electric field components of magnetosonic waves from their magnetic counterparts in the inner magnetosphere is indicated by the results.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
He Zhang, Zhihong Zhong, Rongxin Tang, Xiaohua Deng, Haimeng Li, Dedong Wang
Summary: The study reveals the presence of quasi-periodic whistler-mode waves at the center of a macroscale magnetic hole near Earth's magnetopause, corresponding to electron temperature anisotropy. These waves are accompanied by a significant ultra-low frequency wave of the background magnetic field, exacerbating the evolution of the magnetic hole and contributing to the formation of electron pitch angle distribution.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Yingjie Guo, Binbin Ni, Song Fu, Dedong Wang, Y. Y. Shprits, I. S. Zhelavskaya, Minghang Feng, Deyu Guo
Summary: Using feature selection techniques, this study identified the key geomagnetic and solar wind factors influencing magnetospheric chorus waves, with the AE index with zero-time delay, solar wind speed, and IMF B-z identified as important controlling factors for chorus wave intensity. By combining these factors, a neural network model was developed to predict chorus wave intensity, with the model using the Random Forest method showing the best performance.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
A. Y. Drozdov, H. J. Allison, Y. Y. Shprits, M. E. Usanova, A. Saikin, D. Wang
Summary: In this study, a statistical analysis of PSD minima was conducted to quantify the association between EMIC waves and radiation belt depletions, highlighting the importance of EMIC waves in the dynamics of the radiation belts. Additionally, it was found that approximately 53% of electron depletions in the outer radiation belt core are associated with PSD minima, indicating the common and crucial role of fast localized loss due to interactions with EMIC waves for ultra-relativistic electron populations.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Review
Astronomy & Astrophysics
Yuri Y. Shprits, Hayley J. Allison, Dedong Wang, Alexander Drozdov, Matyas Szabo-Roberts, Irina Zhelavskaya, Ruggero Vasile
Summary: Van Allen Probes measurements have shown the presence of unusual structures in the ultra-relativistic radiation belts, with electromagnetic ion cyclotron waves playing a key role in the efficient loss of ultra-relativistic electrons. The analysis also indicates that local energy diffusion and plasma density depletion are important factors in the acceleration to multi-MeV energies.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Artem Smirnov, Yuri Shprits, Hayley Allison, Nikita Aseev, Alexander Drozdov, Peter Kollmann, Dedong Wang, Anthony A. Saikin
Summary: In this study, the evolution of equatorial electron pitch angle distributions (PADs) in the outer radiation belt region during storm-time was analyzed. The study revealed the variations of PADs at different energies and locations, providing important insights for testing wave models and radiation belt codes.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Astronomy & Astrophysics
He Zhang, Zhihong Zhong, Rongxin Tang, Chengming Liu, Xiaohua Deng, Meng Zhou, Dedong Wang
Summary: In this study, the properties of whistler-mode waves and large-amplitude electrostatic waves in a plasma jet were investigated using the data from the Magnetospheric Multiscale mission. It was found that intense whistler-mode waves were present at the leading part of the plasma jet, while a large-amplitude electrostatic wave was detected at the trailing part. These findings contribute to a better understanding of the kinetic process and wave-particle interaction within plasma jets.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Artem Smirnov, Yuri Y. Shprits, Hayley Allison, Nikita Aseev, Alexander Drozdov, Peter Kollmann, Dedong Wang, Anthony Saikin
Summary: In this study, an empirical model of the equatorial electron pitch angle distributions (PADs) in the outer radiation belt is presented based on collected data from the MagEIS instrument onboard the Van Allen Probes. The model accurately describes various types of PADs and can be used to calculate omnidirectional flux. A two-step modeling procedure is introduced to ensure a continuous dependence on various parameters. Two methods for reconstructing equatorial electron flux using the model are proposed.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2022)
Article
Astronomy & Astrophysics
Bernhard Haas, Yuri Y. Shprits, Hayley J. Allison, Michael Wutzig, Dedong Wang
Summary: Predicting the electron population of Earth's ring current during geomagnetic storms remains a challenging task. This study investigates the sensitivity of ring current electrons to different driving processes during moderate and intense storms. Results show that drift velocities mainly control the behavior of low energy electrons during moderate storms, while loss from wave-particle interactions is critical for quantifying the evolution of intense storms.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Yuri Y. Y. Shprits, Ingo Michaelis, Dedong Wang, Hayley Allison, Ruggero Vasile, Andrei Runov, Alexander Drozdov, Christopher T. Russell, Vladimir Kalegaev, Artem Smirnov
Summary: This study used measurements from the ELFIN-L suit of instruments on the Lomonosov spacecraft to distinguish between stably trapped and drift loss cone electrons. The results show that the loss at MeV energies mainly occurs on the dawn-side, consistent with loss induced by chorus waves.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Bopu Feng, Haimeng Li, Xiongdong Yu, Zhigang Yuan, Rongxin Tang, Dedong Wang, Zhihai Ouyang, Xiaohua Deng
Summary: Exohiss waves are whistler mode waves that resemble hissing sounds and occur outside the plasmapause. These waves can cause similar loss of radiation belt electrons.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
Zhenxia Zhang, Dehe Yang, Dedong Wang, Lu Wang, Fang Zhang, Xinqiao Li, Zhima Zeren
Summary: Based on observations by the China Seismo-Electromagnetic Satellite (CSES), a study reports a typical case of rising-tone quasiperiodic emissions with a large period of around 2 minutes. These emissions can effectively precipitate energetic electrons into the atmosphere in the inner radiation belt. This finding provides new insight into the dynamics of electron precipitation in radiation belt physics.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Katja Stoll, Leonie Pick, Dedong Wang, Xing Cao, Binbin Ni, Yuri Shprits
Summary: Low-energy plasma sheet electrons can be scattered into the atmospheric loss cone and precipitate through resonant wave-particle interactions with electrostatic electron cyclotron harmonic (ECH) waves. The numerical calculation of ECH wave-induced scattering rates requires specifying several parameters, and the exact contribution of scattering by ECH waves to diffuse auroral precipitation is still poorly understood and quantified. This study calculates bounce-averaged quasi-linear scattering rates and compares lifetimes to the strong diffusion limit, finding that plasma density has the greatest impact on electron loss, while hot electron temperature and loss cone parameters have minimal influence. The results depend on an adapted wave normal angle model that represents the growth rate profile more consistently than previous works.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Kedeng Zhang, Huimin Song, Hui Wang, Jing Liu, Wenbin Wang, Xin Wan, Dedong Wang, Yaqi Jin
Summary: This study investigates the dynamic evolution of the polar tongue of ionization (TOI) during a geomagnetic storm using observations and simulations. The results show that neutral winds and ambipolar diffusion play important roles in the evolution of TOI.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Multidisciplinary Sciences
Hayley J. Allison, Yuri Y. Shprits, Irina S. Zhelayskaya, Dedong Wang, Artem G. Smirnov
Summary: The study reveals that under conditions of extremely low plasma density, electrons can be accelerated to ultra-high energies, a phenomenon that occurs only when the plasma number density is very low.