Articles | Volume 35, issue 3
https://doi.org/10.5194/angeo-35-443-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/angeo-35-443-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Regular paper
| 
17 Mar 2017
Regular paper |
| 17 Mar 2017
THEMIS satellite observations of hot flow anomalies at Earth's bow shock
Christina Chu
Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Dr, Fairbanks, AK 99775, USA
Hui Zhang
CORRESPONDING AUTHOR
Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Dr, Fairbanks, AK 99775, USA
David Sibeck
NASA Goddard Spaceflight Center, Greenbelt, Maryland, USA
Antonius Otto
Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Dr, Fairbanks, AK 99775, USA
QiuGang Zong
Institute of Space Physics and Applied Technology, Peking University, Beijing, China
Nick Omidi
Solana Scientifica, San Diego, California, USA
James P. McFadden
Space Sciences Laboratory, University of California Berkeley, Berkeley, California, USA
Dennis Fruehauff
Institute of Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Braunschweig, Germany
Vassilis Angelopoulos
Department of Earth, Planetary, and Space Sciences, University of California Los Angeles, Los Angeles, California, USA
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EGUsphere, https://doi.org/10.5194/egusphere-2024-2956, https://doi.org/10.5194/egusphere-2024-2956, 2024
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The boundary of Earth's magnetic field, the magnetopause, deflects and reacts to the solar wind - the energetic particles emanating from the Sun. We find that certain types of solar wind favour the occurrence of deviations between the magnetopause locations observed by spacecraft and those predicted by models. In addition, the turbulent region in front of the magnetopause, the foreshock, has a large influence on the location of the magnetopause and thus on the accuracy of the model predictions.
Niklas Grimmich, Ferdinand Plaschke, Benjamin Grison, Fabio Prencipe, Christophe Philippe Escoubet, Martin Owain Archer, Ovidiu Dragos Constantinescu, Stein Haaland, Rumi Nakamura, David Gary Sibeck, Fabien Darrouzet, Mykhaylo Hayosh, and Romain Maggiolo
Ann. Geophys., 42, 371–394, https://doi.org/10.5194/angeo-42-371-2024, https://doi.org/10.5194/angeo-42-371-2024, 2024
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In our study, we looked at the boundary between the Earth's magnetic field and the interplanetary magnetic field emitted by the Sun, called the magnetopause. While other studies focus on the magnetopause motion near Earth's Equator, we have studied it in polar regions. The motion of the magnetopause is faster towards the Earth than towards the Sun. We also found that the occurrence of unusual magnetopause locations is due to similar solar influences in the equatorial and polar regions.
Livia R. Alves, Márcio E. S. Alves, Ligia A. da Silva, Vinicius Deggeroni, Paulo R. Jauer, and David G. Sibeck
Ann. Geophys., 41, 429–447, https://doi.org/10.5194/angeo-41-429-2023, https://doi.org/10.5194/angeo-41-429-2023, 2023
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We derive the wave–particle interaction time (IT) equation considering the effects of special relativity theory for whistler-mode chorus waves and relativistic electrons in Earth's radiation belt. Results show that IT has a non-linear dependence on the wave group velocity, electrons' energy, and initial pitch angle. Our results show that the interaction time is generally longer when applying the complete relativistic approach compared to a non-relativistic calculation.
Homayon Aryan, Jacob Bortnik, Jinxing Li, James Michael Weygand, Xiangning Chu, and Vassilis Angelopoulos
Ann. Geophys., 40, 531–544, https://doi.org/10.5194/angeo-40-531-2022, https://doi.org/10.5194/angeo-40-531-2022, 2022
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In this study, we use a multipoint analysis of conjugate magnetospheric and ionospheric observations to investigate the magnetospheric and ionospheric responses to fast flow bursts that are associated with different space weather conditions. The results show that ionospheric currents are connected to the magnetospheric flows for different space weather conditions. The connection is more apparent and global for flows that are associated with a geomagnetically active condition.
Weijie Sun, James A. Slavin, Rumi Nakamura, Daniel Heyner, Karlheinz J. Trattner, Johannes Z. D. Mieth, Jiutong Zhao, Qiu-Gang Zong, Sae Aizawa, Nicolas Andre, and Yoshifumi Saito
Ann. Geophys., 40, 217–229, https://doi.org/10.5194/angeo-40-217-2022, https://doi.org/10.5194/angeo-40-217-2022, 2022
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This paper presents observations of FTE-type flux ropes on the dayside during BepiColombo's Earth flyby. FTE-type flux ropes are a well-known feature of magnetic reconnection on the magnetopause, and they can be used to constrain the location of reconnection X-lines. Our study suggests that the magnetopause X-line passed BepiColombo from the north as it traversed the magnetopause. Moreover, our results also strongly support coalescence creating larger flux ropes by combining smaller ones.
Qiugang Zong
Ann. Geophys., 40, 121–150, https://doi.org/10.5194/angeo-40-121-2022, https://doi.org/10.5194/angeo-40-121-2022, 2022
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Magnetospheric physics is in an extremely vibrant phase, with a number of ongoing and highly successful missions, e.g., Cluster, THEMIS, Van Allen Probes, and the MMS spacecraft, providing the most amazing observations and data sets. Since there are many fundamental and unsolved problems, in this paper I have addressed selected topics of ULF wave–charged particle interactions which encompass many special fields of radiation belt, ring current and plasmaspheric physics.
Ioannis A. Daglis, Loren C. Chang, Sergio Dasso, Nat Gopalswamy, Olga V. Khabarova, Emilia Kilpua, Ramon Lopez, Daniel Marsh, Katja Matthes, Dibyendu Nandy, Annika Seppälä, Kazuo Shiokawa, Rémi Thiéblemont, and Qiugang Zong
Ann. Geophys., 39, 1013–1035, https://doi.org/10.5194/angeo-39-1013-2021, https://doi.org/10.5194/angeo-39-1013-2021, 2021
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We present a detailed account of the science programme PRESTO (PREdictability of the variable Solar–Terrestrial cOupling), covering the period 2020 to 2024. PRESTO was defined by a dedicated committee established by SCOSTEP (Scientific Committee on Solar-Terrestrial Physics). We review the current state of the art and discuss future studies required for the most effective development of solar–terrestrial physics.
Galina Korotova, David Sibeck, Mark Engebretson, Michael Balikhin, Scott Thaller, Craig Kletzing, Harlan Spence, and Robert Redmon
Ann. Geophys., 38, 1267–1281, https://doi.org/10.5194/angeo-38-1267-2020, https://doi.org/10.5194/angeo-38-1267-2020, 2020
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We used multipoint magnetic field, electric field, plasma, and energetic particle observations to study the spatial, temporal, and spectral characteristics of compressional Pc5 pulsations observed deep within the magnetosphere at the end of a strong magnetic storm. We investigated the mode of the waves and their nodal structure. The energetic particles responded directly to the compressional Pc5 pulsations. We interpret the compressional Pc5 waves in terms of drift-mirror instability.
Xingran Chen, Qiugang Zong, Hong Zou, Xuzhi Zhou, Li Li, Yixin Hao, and Yongfu Wang
Ann. Geophys., 38, 801–813, https://doi.org/10.5194/angeo-38-801-2020, https://doi.org/10.5194/angeo-38-801-2020, 2020
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We present a new in situ observation of energetic electrons in space obtained by a newly available particle detector. In view of the characteristic signatures in the particle flux, we attribute the observational features to the drift-resonance wave–particle interaction between energetic electrons and multiple localized ultra-low-frequency waves. The scenario is substantiated by a numerical calculation based on the revised drift-resonance theory which reproduced the observed particle signatures.
Guang Qing Yan, George K. Parks, Chun Lin Cai, Tao Chen, James P. McFadden, and Yong Ren
Ann. Geophys., 38, 263–273, https://doi.org/10.5194/angeo-38-263-2020, https://doi.org/10.5194/angeo-38-263-2020, 2020
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We present (1) K–H vortices in direct response to the northward turning of the interplanetary magnetic field (IMF); (2) solar wind transport into the magnetosphere caused by the K–H vortices, involving both ion and electron fluxes; and (3) typical portraits of the ion and electron fluxes in the regions of plasma transport. The unique characteristics may complement existing observations and enhance our understanding of the K–H vortices and transport process.
Michael Gedalin, Xiaoyan Zhou, Christopher T. Russell, and Vassilis Angelopoulos
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High-resolution measurements of the magnetic profiles of collisionless shocks in space show that large amplitude oscillations appear on the high-magnetic field side. The positions and relative amplitude of these oscillations are shown theoretically to vary in accordance with the potential jump at the shock crossing. The theoretically predicted variety is confirmed by observations.
Ying Zou, Brian M. Walsh, Yukitoshi Nishimura, Vassilis Angelopoulos, J. Michael Ruohoniemi, Kathryn A. McWilliams, and Nozomu Nishitani
Ann. Geophys., 37, 215–234, https://doi.org/10.5194/angeo-37-215-2019, https://doi.org/10.5194/angeo-37-215-2019, 2019
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Magnetopause reconnection is a process whereby the Sun explosively transfers energy to the Earth. Whether the process is spatially patchy or spatially continuous and extended has been under long debate. We use space–ground coordination to overcome the limitations of previous studies and reliably interpret spatial extent. Our result strongly indicates that both patchy and extended reconnection is possible and, interestingly, that extended reconnection grows from a localized patch via spreading.
Shuai Zhang, Anmin Tian, Quanqi Shi, Hanlin Li, Alexander W. Degeling, I. Jonathan Rae, Colin Forsyth, Mengmeng Wang, Xiaochen Shen, Weijie Sun, Shichen Bai, Ruilong Guo, Huizi Wang, Andrew Fazakerley, Suiyan Fu, and Zuyin Pu
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The features of ULF waves are statistically studied on the magnetotail stretched magnetic field lines (8 RE < R < 32 RE) by using 8 years of THEMIS data. The occurrence rates of ULF waves are higher in the post-midnight region than pre-midnight region. The frequency decreases with increasing radial distance of 8–16 RE and could be explained by much more standing waves in this region than in the region of 16–32 RE. The wave frequency is higher after the substorm onset than before it.
Galina Korotova, David Sibeck, Scott Thaller, John Wygant, Harlan Spence, Craig Kletzing, Vassilis Angelopoulos, and Robert Redmon
Ann. Geophys., 36, 1319–1333, https://doi.org/10.5194/angeo-36-1319-2018, https://doi.org/10.5194/angeo-36-1319-2018, 2018
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We employ multipoint observations of the Van Allen Probes, THEMIS, GOES and Cluster to present case and statistical studies of the electromagnetic field, plasma and particle response to interplanetary (IP) shocks observed by Wind. We perform a statistical study of Ey variations of the electric field and associated plasma drift flow velocities for 60 magnetospheric events during the passage of interplanetary shocks.
Minna Palmroth, Heli Hietala, Ferdinand Plaschke, Martin Archer, Tomas Karlsson, Xóchitl Blanco-Cano, David Sibeck, Primož Kajdič, Urs Ganse, Yann Pfau-Kempf, Markus Battarbee, and Lucile Turc
Ann. Geophys., 36, 1171–1182, https://doi.org/10.5194/angeo-36-1171-2018, https://doi.org/10.5194/angeo-36-1171-2018, 2018
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Magnetosheath jets are high-velocity plasma structures that are commonly observed within the Earth's magnetosheath. Previously, they have mainly been investigated with spacecraft observations, which do not allow us to infer their spatial sizes, temporal evolution, or origin. This paper shows for the first time their dimensions, evolution, and origins within a simulation whose dimensions are directly comparable to the Earth's magnetosphere. The results are compared to previous observations.
Yaireska M. Collado-Vega, Virginia L. Kalb, David G. Sibeck, Kyoung-Joo Hwang, and Lutz Rastätter
Ann. Geophys., 36, 1117–1129, https://doi.org/10.5194/angeo-36-1117-2018, https://doi.org/10.5194/angeo-36-1117-2018, 2018
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This paper describes an algorithm that automatically detects vortices around the Earth's magnetosphere using the velocity field from simulated data. It also describes how the tool can be used to analyze further properties of the vortices including the velocity changes within their motion across the magnetosheath. Vortices developed at the magnetopause boundary contribute to the process of mass, momentum and energy transfer from the solar wind into the Earth's magnetosphere.
Xochitl Blanco-Cano, Markus Battarbee, Lucile Turc, Andrew P. Dimmock, Emilia K. J. Kilpua, Sanni Hoilijoki, Urs Ganse, David G. Sibeck, Paul A. Cassak, Robert C. Fear, Riku Jarvinen, Liisa Juusola, Yann Pfau-Kempf, Rami Vainio, and Minna Palmroth
Ann. Geophys., 36, 1081–1097, https://doi.org/10.5194/angeo-36-1081-2018, https://doi.org/10.5194/angeo-36-1081-2018, 2018
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We use the Vlasiator code to study the characteristics of transient structures that exist in the Earth's foreshock, i.e. upstream of the bow shock. The structures are cavitons and spontaneous hot flow anomalies (SHFAs). These transients can interact with the bow shock. We study the changes the shock suffers via this interaction. We also investigate ion distributions associated with the cavitons and SHFAs. A very important result is that the arrival of multiple SHFAs results in shock erosion.
Heqiucen Xu, Kazuo Shiokawa, and Dennis Frühauff
Ann. Geophys., 35, 1131–1142, https://doi.org/10.5194/angeo-35-1131-2017, https://doi.org/10.5194/angeo-35-1131-2017, 2017
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In this study, we statistically analyzed severe magnetic fluctuations in the nightside near-Earth plasma sheet. For the first time, we showed the occurrence rates of these fluctuations. The superposed epoch analysis also indicated that the flow speed increases before the severe magnetic fluctuations. We also discussed how both the inside-out and outside-in substorm models can be used to explain these observed results.
Dennis Frühauff, Johannes Z. D. Mieth, and Karl-Heinz Glassmeier
Ann. Geophys., 35, 253–262, https://doi.org/10.5194/angeo-35-253-2017, https://doi.org/10.5194/angeo-35-253-2017, 2017
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The determination of the polytropic index the plasma sheet of Earth's magnetosphere using THEMIS data. The data set reveals that the active magnetotail density and pressure data are well correlated. Yet, considering broad distributions of specific entropies, the evaluation is best performed on shorter timescales.
Dennis Frühauff, Ferdinand Plaschke, and Karl-Heinz Glassmeier
Ann. Geophys., 35, 117–121, https://doi.org/10.5194/angeo-35-117-2017, https://doi.org/10.5194/angeo-35-117-2017, 2017
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Vector magnetic field instruments mounted on spacecraft require precise in-flight calibration of the offsets of all three axes, i.e., the output in vanishing ambient field. While calibration of the spin plane offsets is trivial, we apply a new technique for determining the spin axis offset, not relying on solar wind data but on magnetosheath encounters. This technique is successfully applied to the satellites of the THEMIS mission to update the calibration parameters of the complete mission.
Galina Korotova, David Sibeck, Mark Engebretson, John Wygant, Scott Thaller, Harlan Spence, Craig Kletzing, Vassilis Angelopoulos, and Robert Redmon
Ann. Geophys., 34, 985–998, https://doi.org/10.5194/angeo-34-985-2016, https://doi.org/10.5194/angeo-34-985-2016, 2016
Dennis Frühauff and Karl-Heinz Glassmeier
Ann. Geophys., 34, 399–409, https://doi.org/10.5194/angeo-34-399-2016, https://doi.org/10.5194/angeo-34-399-2016, 2016
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This study presents an investigation on the occurrence of fast flows in the magnetotail using the complete available data set of the THEMIS spacecraft for the years 2007 to 2015. First, basic statistical findings concerning velocity distributions, occurrence rates, group structures and key features of 16 000 events are presented using Superposed Epoch and Minimum Variance Analysis techniques.
I. Richter, C. Koenders, H.-U. Auster, D. Frühauff, C. Götz, P. Heinisch, C. Perschke, U. Motschmann, B. Stoll, K. Altwegg, J. Burch, C. Carr, E. Cupido, A. Eriksson, P. Henri, R. Goldstein, J.-P. Lebreton, P. Mokashi, Z. Nemeth, H. Nilsson, M. Rubin, K. Szegö, B. T. Tsurutani, C. Vallat, M. Volwerk, and K.-H. Glassmeier
Ann. Geophys., 33, 1031–1036, https://doi.org/10.5194/angeo-33-1031-2015, https://doi.org/10.5194/angeo-33-1031-2015, 2015
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We present a first report on magnetic field measurements made in the coma of comet 67P/C-G in its low-activity state. The plasma environment is dominated by quasi-coherent, large-amplitude, compressional magnetic field oscillations around 40mHz, differing from the observations at strongly active comets where waves at the cometary ion gyro-frequencies are the main feature. We propose a cross-field current instability associated with the newborn cometary ions as a possible source mechanism.
G. I. Korotova, D. G. Sibeck, K. Tahakashi, L. Dai, H. E. Spence, C. A. Kletzing, J. R. Wygant, J. W. Manweiler, P. S. Moya, K.-J. Hwang, and R. J. Redmon
Ann. Geophys., 33, 955–964, https://doi.org/10.5194/angeo-33-955-2015, https://doi.org/10.5194/angeo-33-955-2015, 2015
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We studied localized Pc 4 pulsations in the pre-midnight inner magnetosphere observed by Van Allen Probe B on May 1 2013. Although we attribute the pulsations to a drift-bounce resonance, we demonstrate that the energy-dependent response of the ion fluxes result from pulsation-associated velocities sweeping energy-dependent radial ion flux gradients back and forth past the spacecraft.
I. I. Vogiatzis, A. Isavnin, Q.-G. Zong, E. T. Sarris, S. W. Lu, and A. M. Tian
Ann. Geophys., 33, 63–74, https://doi.org/10.5194/angeo-33-63-2015, https://doi.org/10.5194/angeo-33-63-2015, 2015
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Magnetospheric substorms are one of the most important phenomena occurring in planetary magnetotails, dynamically reconfiguring the near- planet space environment. They encompass various fundamental processes of plasma acceleration and transport in the magnetosphere/ionosphere. The key features of the paper are a new magnetospheric substorm model, a new explanation about the origin of dipolarization fronts (DFs), and a new explanation for energetic ion acceleration/injection in front of DFs.
S. Machida, Y. Miyashita, A. Ieda, M. Nosé, V. Angelopoulos, and J. P. McFadden
Ann. Geophys., 32, 99–111, https://doi.org/10.5194/angeo-32-99-2014, https://doi.org/10.5194/angeo-32-99-2014, 2014
F. Plaschke, H. Hietala, and V. Angelopoulos
Ann. Geophys., 31, 1877–1889, https://doi.org/10.5194/angeo-31-1877-2013, https://doi.org/10.5194/angeo-31-1877-2013, 2013
F. R. Cardoso, W. D. Gonzalez, D. G. Sibeck, M. Kuznetsova, and D. Koga
Ann. Geophys., 31, 1853–1866, https://doi.org/10.5194/angeo-31-1853-2013, https://doi.org/10.5194/angeo-31-1853-2013, 2013
Y. M. Collado-Vega, R. L. Kessel, D. G. Sibeck, V. L. Kalb, R. A. Boller, and L. Rastaetter
Ann. Geophys., 31, 1463–1483, https://doi.org/10.5194/angeo-31-1463-2013, https://doi.org/10.5194/angeo-31-1463-2013, 2013
J. Liang, F. Jiang, E. Donovan, E. Spanswick, V. Angelopoulos, and R. Strangeway
Ann. Geophys., 31, 1077–1101, https://doi.org/10.5194/angeo-31-1077-2013, https://doi.org/10.5194/angeo-31-1077-2013, 2013
A. Alexandrova, R. Nakamura, V. S. Semenov, I. V. Kubyshkin, S. Apatenkov, E. V. Panov, D. Korovinskiy, H. Biernat, W. Baumjohann, K.-H. Glassmeier, and J. P. McFadden
Ann. Geophys., 30, 1727–1741, https://doi.org/10.5194/angeo-30-1727-2012, https://doi.org/10.5194/angeo-30-1727-2012, 2012
Short summary
Hot flow anomalies (HFAs) at Earth's bow shock were identified in Time History of Events and Macroscale Interactions During Substorms (THEMIS) satellite data from 2007 to 2009. The events were classified as young or mature and regular or spontaneous hot flow anomalies (SHFAs). HFA–SHFA occurrence decreases with distance upstream from the bow shock. HFAs are more prevalent for radial interplanetary magnetic fields and solar wind speeds from 550 to 600 kms−1.
Hot flow anomalies (HFAs) at Earth's bow shock were identified in Time History of Events and...
