Articles | Volume 39, issue 4
https://doi.org/10.5194/angeo-39-571-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-39-571-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
02 Jul 2021
Regular paper |
| 02 Jul 2021
| 02 Jul 2021
Evidence of the nonstationarity of the terrestrial bow shock from multi-spacecraft observations: methodology, results, and quantitative comparison with particle-in-cell (PIC) simulations
IRAP, CNRS, University of Toulouse, UPS, CNES, Toulouse, 31400,
France
Bertrand Lembège
LATMOS, CNRS, University of Versailles Saint-Quentin, Guyancourt, 78390,
France
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Martin Volwerk, Cyril Simon Wedlund, David Mautner, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Christian Mazelle, Diana Rojas-Castillo, César Bertucci, and Magda Delva
Ann. Geophys., 41, 389–408, https://doi.org/10.5194/angeo-41-389-2023, https://doi.org/10.5194/angeo-41-389-2023, 2023
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Freshly created ions in solar wind start gyrating around the interplanetary magnetic field. When they cross the bow shock, they get an extra kick, and this increases the plasma pressure against the magnetic pressure. This leads to the creation of so-called mirror modes, regions where the magnetic field decreases in strength and the plasma density increases. These structures help in exploring how energy is transferred from the ions to the magnetic field and where around Venus this is happening.
Cyril Simon Wedlund, Martin Volwerk, Christian Mazelle, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Jasper Halekas, Diana Rojas-Castillo, César Bertucci, and Jared Espley
Ann. Geophys., 41, 225–251, https://doi.org/10.5194/angeo-41-225-2023, https://doi.org/10.5194/angeo-41-225-2023, 2023
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Mirror modes are magnetic bottles found in the space plasma environment of planets contributing to the energy exchange with the solar wind. We use magnetic field measurements from the NASA Mars Atmosphere and Volatile EvolutioN mission to detect them around Mars and show how they evolve in time and space. The structures concentrate in two regions: one behind the bow shock and the other closer to the planet. They compete with other wave modes depending on the solar flux and heliocentric distance.
Martin Volwerk, Cyril Simon Wedlund, David Mautner, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Christian Mazelle, Diana Rojas-Castillo, César Bertucci, and Magda Delva
Ann. Geophys., 41, 389–408, https://doi.org/10.5194/angeo-41-389-2023, https://doi.org/10.5194/angeo-41-389-2023, 2023
Short summary
Short summary
Freshly created ions in solar wind start gyrating around the interplanetary magnetic field. When they cross the bow shock, they get an extra kick, and this increases the plasma pressure against the magnetic pressure. This leads to the creation of so-called mirror modes, regions where the magnetic field decreases in strength and the plasma density increases. These structures help in exploring how energy is transferred from the ions to the magnetic field and where around Venus this is happening.
Cyril Simon Wedlund, Martin Volwerk, Christian Mazelle, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Jasper Halekas, Diana Rojas-Castillo, César Bertucci, and Jared Espley
Ann. Geophys., 41, 225–251, https://doi.org/10.5194/angeo-41-225-2023, https://doi.org/10.5194/angeo-41-225-2023, 2023
Short summary
Short summary
Mirror modes are magnetic bottles found in the space plasma environment of planets contributing to the energy exchange with the solar wind. We use magnetic field measurements from the NASA Mars Atmosphere and Volatile EvolutioN mission to detect them around Mars and show how they evolve in time and space. The structures concentrate in two regions: one behind the bow shock and the other closer to the planet. They compete with other wave modes depending on the solar flux and heliocentric distance.
Philippe Savoini and Bertrand Lembège
Ann. Geophys., 38, 1217–1235, https://doi.org/10.5194/angeo-38-1217-2020, https://doi.org/10.5194/angeo-38-1217-2020, 2020
Short summary
Short summary
Numerical simulations have been used to investigate some acceleration mechanisms in order to explain the origin of the energized back-streaming ions observed at the Earth's bow shock. This paper used test particles in two different configurations with self-consistent and fixed shock front profiles. The comparison of these two configurations allows us to analyze, in detail, the impact of the shock front nonstationarity and the role of the built-up electric field in the acceleration process.
Related subject area
Subject: Magnetosphere & space plasma physics | Keywords: Bow shock and foreshock
Fine structure and motion of the bow shock and particle energisation mechanisms inferred from Magnetospheric Multiscale (MMS) observations
Foreshock cavitons and spontaneous hot flow anomalies: a statistical study with a global hybrid-Vlasov simulation
A deep insight into the ion foreshock with the help of test particle two-dimensional simulations
Helium in the Earth's foreshock: a global Vlasiator survey
Non-locality of Earth's quasi-parallel bow shock: injection of thermal protons in a hybrid-Vlasov simulation
Low-frequency magnetic variations at the high-β Earth bow shock
Comment on “Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation” by Blanco-Cano et al. (2018)
Reflection of the strahl within the foot of the Earth's bow shock
Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation
Krzysztof Stasiewicz and Zbigniew Kłos
Ann. Geophys., 40, 315–325, https://doi.org/10.5194/angeo-40-315-2022, https://doi.org/10.5194/angeo-40-315-2022, 2022
Short summary
Short summary
The acceleration, or energisation, of particles is a common and fundamental process throughout the universe. This study presents new observations of the acceleration of protons by waves at the bow shock upstream of the Earth, where the solar wind first encounters Earth’s magnetic field. The results are important, because they provide insight into acceleration processes that can create high-energy particles both near the Earth and at other astrophysical systems.
Vertti Tarvus, Lucile Turc, Markus Battarbee, Jonas Suni, Xóchitl Blanco-Cano, Urs Ganse, Yann Pfau-Kempf, Markku Alho, Maxime Dubart, Maxime Grandin, Andreas Johlander, Konstantinos Papadakis, and Minna Palmroth
Ann. Geophys., 39, 911–928, https://doi.org/10.5194/angeo-39-911-2021, https://doi.org/10.5194/angeo-39-911-2021, 2021
Short summary
Short summary
We use simulations of Earth's magnetosphere and study the formation of transient wave structures in the region where the solar wind first interacts with the magnetosphere. These transients move earthward and play a part in the solar wind–magnetosphere interaction. We show that the transients are a common feature and their properties are altered as they move earthward, including an increase in temperature, decrease in solar wind speed and an alteration in their propagation properties.
Philippe Savoini and Bertrand Lembège
Ann. Geophys., 38, 1217–1235, https://doi.org/10.5194/angeo-38-1217-2020, https://doi.org/10.5194/angeo-38-1217-2020, 2020
Short summary
Short summary
Numerical simulations have been used to investigate some acceleration mechanisms in order to explain the origin of the energized back-streaming ions observed at the Earth's bow shock. This paper used test particles in two different configurations with self-consistent and fixed shock front profiles. The comparison of these two configurations allows us to analyze, in detail, the impact of the shock front nonstationarity and the role of the built-up electric field in the acceleration process.
Markus Battarbee, Xóchitl Blanco-Cano, Lucile Turc, Primož Kajdič, Andreas Johlander, Vertti Tarvus, Stephen Fuselier, Karlheinz Trattner, Markku Alho, Thiago Brito, Urs Ganse, Yann Pfau-Kempf, Mojtaba Akhavan-Tafti, Tomas Karlsson, Savvas Raptis, Maxime Dubart, Maxime Grandin, Jonas Suni, and Minna Palmroth
Ann. Geophys., 38, 1081–1099, https://doi.org/10.5194/angeo-38-1081-2020, https://doi.org/10.5194/angeo-38-1081-2020, 2020
Short summary
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We investigate the dynamics of helium in the foreshock, a part of near-Earth space found upstream of the Earth's bow shock. We show how the second most common ion in interplanetary space reacts strongly to plasma waves found in the foreshock. Spacecraft observations and supercomputer simulations both give us a new understanding of the foreshock edge and how to interpret future observations.
Markus Battarbee, Urs Ganse, Yann Pfau-Kempf, Lucile Turc, Thiago Brito, Maxime Grandin, Tuomas Koskela, and Minna Palmroth
Ann. Geophys., 38, 625–643, https://doi.org/10.5194/angeo-38-625-2020, https://doi.org/10.5194/angeo-38-625-2020, 2020
Short summary
Short summary
The structure and medium-scale dynamics of Earth's bow shock and how charged solar wind particles are reflected by it are studied in order to better understand space weather effects. We use advanced supercomputer simulations to model the shock and reflected ions. We find that the thickness of the shock depends on solar wind conditions but also has small-scale variations. Charged particle reflection is shown to be non-localized. Magnetic fields are important for ion reflection.
Anatoli A. Petrukovich, Olga M. Chugunova, and Pavel I. Shustov
Ann. Geophys., 37, 877–889, https://doi.org/10.5194/angeo-37-877-2019, https://doi.org/10.5194/angeo-37-877-2019, 2019
Short summary
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Earth's bow shock in solar wind with high thermal and low magnetic pressure is a rare phenomenon. However, such an object is ubiquitous in astrophysical plasmas.
We surveyed statistics of such shock observations since 1995. About 100 crossings were initially identified. In this report 22 crossings from the Cluster project were studied using multipoint analysis, which allowed for the determination of the spatial scales of the shock transition and of the dominant magnetic variations
Gábor Facskó
Ann. Geophys., 37, 763–764, https://doi.org/10.5194/angeo-37-763-2019, https://doi.org/10.5194/angeo-37-763-2019, 2019
Short summary
Short summary
Blanco-Cano et al. (2018) intended to find a type of transient event in the solar wind before the terrestrial bow shock using a special type of simulation. However, the simulation results cannot reproduce the main features of the event. Based on the remarks described below, I am sure that the features in the simulations are not those types of events. The Vlasiator code simulated proto-SHFAs.
Christopher A. Gurgiolo, Melvyn L. Goldstein, and Adolfo Viñas
Ann. Geophys., 37, 243–261, https://doi.org/10.5194/angeo-37-243-2019, https://doi.org/10.5194/angeo-37-243-2019, 2019
Short summary
Short summary
The reflection of solar wind electrons at the bow shock helps define the physical properties of the foreshock, the region where the interplanetary magnetic field directly connects to the bow shock. We report that the strahl, the field-aligned component of the electron solar wind distribution, appears to be nearly fully reflected at the bow shock and that the reflection occurs in the foot of the shock, implying that mirroring is not the primary cause of the electron reflection.
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
Short summary
Short summary
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.
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Short summary
Nonstationarity of the quasi-perpendicular terrestrial bow shock is analyzed from magnetic field measurements, comparison with 2D particle-in-cell (PIC) simulations, and a careful and accurate methodology in the data processing. The results show evidence of a strong variability of the microstructures of the shock front (foot and ramp), confirming the importance of dissipative effects. These results indicate that these features can be signatures of the shock front self-reformation.
Nonstationarity of the quasi-perpendicular terrestrial bow shock is analyzed from magnetic field...
