Articles | Volume 36, issue 4
https://doi.org/10.5194/angeo-36-1081-2018
© Author(s) 2018. 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-36-1081-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
08 Aug 2018
Regular paper |
| 08 Aug 2018
| 08 Aug 2018
Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation
Xochitl Blanco-Cano
CORRESPONDING AUTHOR
Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
Markus Battarbee
Department of Physics, University of Helsinki, Helsinki, Finland
Lucile Turc
Department of Physics, University of Helsinki, Helsinki, Finland
Andrew P. Dimmock
Swedish Institute of Space Physics, Uppsala, Sweden
Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, Espoo, Finland
Emilia K. J. Kilpua
Department of Physics, University of Helsinki, Helsinki, Finland
Sanni Hoilijoki
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, USA
Urs Ganse
Department of Physics, University of Helsinki, Helsinki, Finland
David G. Sibeck
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Paul A. Cassak
Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia, USA
Robert C. Fear
Department of Physics and Astronomy, University of Southampton, Southampton, UK
Riku Jarvinen
Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, Espoo, Finland
Finnish Meteorological Institute, Helsinki, Finland
Liisa Juusola
Finnish Meteorological Institute, Helsinki, Finland
Department of Physics, University of Helsinki, Helsinki, Finland
Yann Pfau-Kempf
Department of Physics, University of Helsinki, Helsinki, Finland
Rami Vainio
Department of Physics and Astronomy, University of Turku, Turku, Finland
Minna Palmroth
Department of Physics, University of Helsinki, Helsinki, Finland
Finnish Meteorological Institute, Helsinki, Finland
Related authors
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.
Minna Palmroth, Savvas Raptis, Jonas Suni, Tomas Karlsson, Lucile Turc, Andreas Johlander, Urs Ganse, Yann Pfau-Kempf, Xochitl Blanco-Cano, Mojtaba Akhavan-Tafti, Markus Battarbee, Maxime Dubart, Maxime Grandin, Vertti Tarvus, and Adnane Osmane
Ann. Geophys., 39, 289–308, https://doi.org/10.5194/angeo-39-289-2021, https://doi.org/10.5194/angeo-39-289-2021, 2021
Short summary
Short summary
Magnetosheath jets are high-velocity features within the Earth's turbulent magnetosheath, separating the Earth's magnetic domain from the solar wind. The characteristics of the jets are difficult to assess statistically as a function of their lifetime because normally spacecraft observe them only at one position within the magnetosheath. This study first confirms the accuracy of the model used, Vlasiator, by comparing it to MMS spacecraft, and then carries out the first jet lifetime statistics.
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
Short summary
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.
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
Short summary
Short summary
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.
P. Kajdič, X. Blanco-Cano, N. Omidi, K. Meziane, C. T. Russell, J.-A. Sauvaud, I. Dandouras, and B. Lavraud
Ann. Geophys., 31, 2163–2178, https://doi.org/10.5194/angeo-31-2163-2013, https://doi.org/10.5194/angeo-31-2163-2013, 2013
Yann Pfau-Kempf, Konstantinos Papadakis, Markku Alho, Markus Battarbee, Giulia Cozzani, Lauri Pänkäläinen, Urs Ganse, Fasil Kebede, Jonas Suni, Konstantinos Horaites, Maxime Grandin, and Minna Palmroth
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-26, https://doi.org/10.5194/angeo-2024-26, 2024
Preprint under review for ANGEO
Short summary
Short summary
Flux ropes are peculiar structures of twisted magnetic field occurring in many regions of space, near Earth and other planets, at the Sun, and in astrophysical objects. We developed a new way of detecting flux ropes in large supercomputer simulations of near-Earth space and we use it to follow the evolution of flux ropes for long distances past the Earth in the flow direction. This will be useful in future studies as these flux ropes are involved in the transport of matter and energy in space.
Niklas Grimmich, Adrian Pöppelwerth, Martin Owain Archer, David Gary Sibeck, Ferdinand Plaschke, Wenli Mo, Vicki Toy-Edens, Drew Lawson Turner, Hyangpyo Kim, and Rumi Nakamura
EGUsphere, https://doi.org/10.5194/egusphere-2024-2956, https://doi.org/10.5194/egusphere-2024-2956, 2024
Short summary
Short summary
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
Short summary
Short summary
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.
Leo Kotipalo, Markus Battarbee, Yann Pfau-Kempf, and Minna Palmroth
Geosci. Model Dev., 17, 6401–6413, https://doi.org/10.5194/gmd-17-6401-2024, https://doi.org/10.5194/gmd-17-6401-2024, 2024
Short summary
Short summary
This paper examines a method called adaptive mesh refinement in optimization of the space plasma simulation model Vlasiator. The method locally adjusts resolution in regions which are most relevant to modelling, based on the properties of the plasma. The runs testing this method show that adaptive refinement manages to highlight the desired regions with manageable performance overhead. Performance in larger-scale production runs and mitigation of overhead are avenues of further research.
Urs Ganse, Yann Pfau-Kempf, Hongyang Zhou, Liisa Juusola, Abiyot Workayehu, Fasil Kebede, Konstantinos Papadakis, Maxime Grandin, Markku Alho, Markus Battarbee, Maxime Dubart, Leo Kotipalo, Arnaud Lalagüe, Jonas Suni, Konstantinos Horaites, and Minna Palmroth
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2024-101, https://doi.org/10.5194/gmd-2024-101, 2024
Revised manuscript accepted for GMD
Short summary
Short summary
Vlasiator is a kinetic space-plasma model that simulates the behaviour of plasma, solar wind and magnetic fields in near-Earth space. So far, these simulations had been run without any interaction wtih the ionosphere, the uppermost layer of Earth's atmosphere. In this manuscript, we present the new methods that add an ionospheric electrodynamics model to Vlasiator, coupling it with the existing methods and presenting new simulation results of how space Plasma and Earth's ionosphere interact.
Tuomas Häkkilä, Maxime Grandin, Markus Battarbee, Monika E. Szeląg, Markku Alho, Leo Kotipalo, Niilo Kalakoski, Pekka T. Verronen, and Minna Palmroth
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-7, https://doi.org/10.5194/angeo-2024-7, 2024
Revised manuscript under review for ANGEO
Short summary
Short summary
We study the atmospheric impact of auroral electron precipitation, by the novel combination of both magnetospheric and atmospheric modelling. We first simulate fluxes of auroral electrons, and then use these fluxes to model their atmospheric impact. We find an increase of up to 200 % in thermospheric odd nitrogen, and a corresponding decrease in stratospheric ozone of around 0.7 %. The produced auroral electron precipitation is realistic, and shows the potential for future studies.
Emilia K. J. Kilpua, Simon Good, Matti Ala-Lahti, Adnane Osmane, and Venla Koikkalainen
Ann. Geophys., 42, 163–177, https://doi.org/10.5194/angeo-42-163-2024, https://doi.org/10.5194/angeo-42-163-2024, 2024
Short summary
Short summary
The solar wind is organised into slow and fast streams, interaction regions, and transient structures originating from solar eruptions. Their internal characteristics are not well understood. A more comprehensive understanding of such features can give insight itno physical processes governing their formation and evolution. Using tools from information theory, we find that the solar wind shows universal turbulent properties on smaller scales, while on larger scales, clear differences arise.
Markku Alho, Giulia Cozzani, Ivan Zaitsev, Fasil Tesema Kebede, Urs Ganse, Markus Battarbee, Maarja Bussov, Maxime Dubart, Sanni Hoilijoki, Leo Kotipalo, Konstantinos Papadakis, Yann Pfau-Kempf, Jonas Suni, Vertti Tarvus, Abiyot Workayehu, Hongyang Zhou, and Minna Palmroth
Ann. Geophys., 42, 145–161, https://doi.org/10.5194/angeo-42-145-2024, https://doi.org/10.5194/angeo-42-145-2024, 2024
Short summary
Short summary
Magnetic reconnection is one of the main processes for energy conversion and plasma transport in space plasma physics, associated with plasma entry into the magnetosphere of Earth and Earth’s substorm cycle. Global modelling of these plasma processes enables us to understand the magnetospheric system in detail. However, finding sites of active reconnection from large simulation datasets can be challenging, and this paper develops tools to find magnetic topologies related to reconnection.
Sanni Hoilijoki, Emilia Kilpua, Adnane Osmane, Lucile Turc, Mikko Savola, Veera Lipsanen, Harriet George, and Milla Kalliokoski
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-3, https://doi.org/10.5194/angeo-2024-3, 2024
Revised manuscript under review for ANGEO
Short summary
Short summary
Structures originating from the Sun, such as coronal mass ejections and high-speed streams, may impact the Earth's magnetosphere differently. The occurrence rate of these structures depends on the phase solar cycle. We use mutual information to study the change in the statistical dependence between solar wind and inner magnetosphere. We find that the non-linearity between solar wind and inner magnetosphere varies over the solar cycle and during different solar wind drivers.
Jonas Suni, Minna Palmroth, Lucile Turc, Markus Battarbee, Giulia Cozzani, Maxime Dubart, Urs Ganse, Harriet George, Evgeny Gordeev, Konstantinos Papadakis, Yann Pfau-Kempf, Vertti Tarvus, Fasil Tesema, and Hongyang Zhou
Ann. Geophys., 41, 551–568, https://doi.org/10.5194/angeo-41-551-2023, https://doi.org/10.5194/angeo-41-551-2023, 2023
Short summary
Short summary
Magnetosheath jets are structures of enhanced plasma density and/or velocity in a region of near-Earth space known as the magnetosheath. When they propagate towards the Earth, these jets can disturb the Earth's magnetic field and cause hazards for satellites. In this study, we use a simulation called Vlasiator to model near-Earth space and investigate jets using case studies and statistical analysis. We find that jets that propagate towards the Earth are different from jets that do not.
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
Short summary
Short summary
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.
Liisa Juusola, Ari Viljanen, Andrew P. Dimmock, Mirjam Kellinsalmi, Audrey Schillings, and James M. Weygand
Ann. Geophys., 41, 13–37, https://doi.org/10.5194/angeo-41-13-2023, https://doi.org/10.5194/angeo-41-13-2023, 2023
Short summary
Short summary
We have examined events during which the measured magnetic field on the ground changes very rapidly, causing a risk to technological conductor networks. According to our results, such events occur when strong electric currents in the ionosphere at 100 km altitude are abruptly modified by sudden compression or expansion of the magnetospheric magnetic field farther in space.
Konstantinos Papadakis, Yann Pfau-Kempf, Urs Ganse, Markus Battarbee, Markku Alho, Maxime Grandin, Maxime Dubart, Lucile Turc, Hongyang Zhou, Konstantinos Horaites, Ivan Zaitsev, Giulia Cozzani, Maarja Bussov, Evgeny Gordeev, Fasil Tesema, Harriet George, Jonas Suni, Vertti Tarvus, and Minna Palmroth
Geosci. Model Dev., 15, 7903–7912, https://doi.org/10.5194/gmd-15-7903-2022, https://doi.org/10.5194/gmd-15-7903-2022, 2022
Short summary
Short summary
Vlasiator is a plasma simulation code that simulates the entire near-Earth space at a global scale. As 6D simulations require enormous amounts of computational resources, Vlasiator uses adaptive mesh refinement (AMR) to lighten the computational burden. However, due to Vlasiator’s grid topology, AMR simulations suffer from grid aliasing artifacts that affect the global results. In this work, we present and evaluate the performance of a mechanism for alleviating those artifacts.
Adnane Osmane, Mikko Savola, Emilia Kilpua, Hannu Koskinen, Joseph E. Borovsky, and Milla Kalliokoski
Ann. Geophys., 40, 37–53, https://doi.org/10.5194/angeo-40-37-2022, https://doi.org/10.5194/angeo-40-37-2022, 2022
Short summary
Short summary
It has long been known that particles get accelerated close to the speed of light in the near-Earth space environment. Research in the last decades has also clarified what processes and waves are responsible for the acceleration of particles. However, it is difficult to quantify the scale of the impact of various processes competing with one another. In this study we present a methodology to quantify the impact waves can have on energetic particles.
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
Short summary
Short summary
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.
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.
Andrei Runov, Maxime Grandin, Minna Palmroth, Markus Battarbee, Urs Ganse, Heli Hietala, Sanni Hoilijoki, Emilia Kilpua, Yann Pfau-Kempf, Sergio Toledo-Redondo, Lucile Turc, and Drew Turner
Ann. Geophys., 39, 599–612, https://doi.org/10.5194/angeo-39-599-2021, https://doi.org/10.5194/angeo-39-599-2021, 2021
Short summary
Short summary
In collisionless systems like space plasma, particle velocity distributions contain fingerprints of ongoing physical processes. However, it is challenging to decode this information from observations. We used hybrid-Vlasov simulations to obtain ion velocity distribution functions at different locations and at different stages of the Earth's magnetosphere dynamics. The obtained distributions provide valuable examples that may be directly compared with observations by satellites in space.
Minna Palmroth, Savvas Raptis, Jonas Suni, Tomas Karlsson, Lucile Turc, Andreas Johlander, Urs Ganse, Yann Pfau-Kempf, Xochitl Blanco-Cano, Mojtaba Akhavan-Tafti, Markus Battarbee, Maxime Dubart, Maxime Grandin, Vertti Tarvus, and Adnane Osmane
Ann. Geophys., 39, 289–308, https://doi.org/10.5194/angeo-39-289-2021, https://doi.org/10.5194/angeo-39-289-2021, 2021
Short summary
Short summary
Magnetosheath jets are high-velocity features within the Earth's turbulent magnetosheath, separating the Earth's magnetic domain from the solar wind. The characteristics of the jets are difficult to assess statistically as a function of their lifetime because normally spacecraft observe them only at one position within the magnetosheath. This study first confirms the accuracy of the model used, Vlasiator, by comparing it to MMS spacecraft, and then carries out the first jet lifetime statistics.
Minna Palmroth, Maxime Grandin, Theodoros Sarris, Eelco Doornbos, Stelios Tourgaidis, Anita Aikio, Stephan Buchert, Mark A. Clilverd, Iannis Dandouras, Roderick Heelis, Alex Hoffmann, Nickolay Ivchenko, Guram Kervalishvili, David J. Knudsen, Anna Kotova, Han-Li Liu, David M. Malaspina, Günther March, Aurélie Marchaudon, Octav Marghitu, Tomoko Matsuo, Wojciech J. Miloch, Therese Moretto-Jørgensen, Dimitris Mpaloukidis, Nils Olsen, Konstantinos Papadakis, Robert Pfaff, Panagiotis Pirnaris, Christian Siemes, Claudia Stolle, Jonas Suni, Jose van den IJssel, Pekka T. Verronen, Pieter Visser, and Masatoshi Yamauchi
Ann. Geophys., 39, 189–237, https://doi.org/10.5194/angeo-39-189-2021, https://doi.org/10.5194/angeo-39-189-2021, 2021
Short summary
Short summary
This is a review paper that summarises the current understanding of the lower thermosphere–ionosphere (LTI) in terms of measurements and modelling. The LTI is the transition region between space and the atmosphere and as such of tremendous importance to both the domains of space and atmosphere. The paper also serves as the background for European Space Agency Earth Explorer 10 candidate mission Daedalus.
Markus Battarbee, Thiago Brito, Markku Alho, Yann Pfau-Kempf, Maxime Grandin, Urs Ganse, Konstantinos Papadakis, Andreas Johlander, Lucile Turc, Maxime Dubart, and Minna Palmroth
Ann. Geophys., 39, 85–103, https://doi.org/10.5194/angeo-39-85-2021, https://doi.org/10.5194/angeo-39-85-2021, 2021
Short summary
Short summary
We investigate local acceleration dynamics of electrons with a new numerical simulation method, which is an extension of a world-leading kinetic plasma simulation. We describe how large supercomputer simulations can be used to initialize the electron simulations and show numerical stability for the electron method. We show that features of our simulated electrons match observations from Earth's magnetic tail region.
Maxime Dubart, Urs Ganse, Adnane Osmane, Andreas Johlander, Markus Battarbee, Maxime Grandin, Yann Pfau-Kempf, Lucile Turc, and Minna Palmroth
Ann. Geophys., 38, 1283–1298, https://doi.org/10.5194/angeo-38-1283-2020, https://doi.org/10.5194/angeo-38-1283-2020, 2020
Short summary
Short summary
Plasma waves are ubiquitous in the Earth's magnetosphere. They are responsible for many energetic processes happening in Earth's atmosphere, such as auroras. In order to understand these processes, thorough investigations of these waves are needed. We use a state-of-the-art numerical model to do so. Here we investigate the impact of different spatial resolutions in the model on these waves in order to improve in the future the model without wasting computational resources.
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
Short summary
Short summary
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.
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
Short summary
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.
Lucile Turc, Vertti Tarvus, Andrew P. Dimmock, Markus Battarbee, Urs Ganse, Andreas Johlander, Maxime Grandin, Yann Pfau-Kempf, Maxime Dubart, and Minna Palmroth
Ann. Geophys., 38, 1045–1062, https://doi.org/10.5194/angeo-38-1045-2020, https://doi.org/10.5194/angeo-38-1045-2020, 2020
Short summary
Short summary
Using global computer simulations, we study properties of the magnetosheath, the region of near-Earth space where the stream of particles originating from the Sun, the solar wind, is slowed down and deflected around the Earth's magnetic field. One of our main findings is that even for idealised solar wind conditions as used in our model, the magnetosheath density shows large-scale spatial and temporal variation in the so-called quasi-parallel magnetosheath, causing varying levels of asymmetry.
Emilia K. J. Kilpua, Dominique Fontaine, Simon W. Good, Matti Ala-Lahti, Adnane Osmane, Erika Palmerio, Emiliya Yordanova, Clement Moissard, Lina Z. Hadid, and Miho Janvier
Ann. Geophys., 38, 999–1017, https://doi.org/10.5194/angeo-38-999-2020, https://doi.org/10.5194/angeo-38-999-2020, 2020
Short summary
Short summary
This paper studies magnetic field fluctuations in three turbulent sheath regions ahead of interplanetary coronal mass ejections (ICMEs) in the near-Earth solar wind. Our results show that fluctuation properties vary significantly in different parts of the sheath when compared to solar wind ahead. Turbulence in sheaths resembles that of the slow solar wind in the terrestrial magnetosheath, e.g. regarding compressibility and intermittency, and it often lacks Kolmogorov's spectral indices.
Harriet George, Emilia Kilpua, Adnane Osmane, Timo Asikainen, Milla M. H. Kalliokoski, Craig J. Rodger, Stepan Dubyagin, and Minna Palmroth
Ann. Geophys., 38, 931–951, https://doi.org/10.5194/angeo-38-931-2020, https://doi.org/10.5194/angeo-38-931-2020, 2020
Short summary
Short summary
We compared trapped outer radiation belt electron fluxes to high-latitude precipitating electron fluxes during two interplanetary coronal mass ejections (ICMEs) with opposite magnetic cloud rotation. The electron response had many similarities and differences between the two events, indicating that different acceleration mechanisms acted. Van Allen Probe data were used for trapped electron flux measurements, and Polar Operational Environmental Satellites were used for precipitating flux data.
Milla M. H. Kalliokoski, Emilia K. J. Kilpua, Adnane Osmane, Drew L. Turner, Allison N. Jaynes, Lucile Turc, Harriet George, and Minna Palmroth
Ann. Geophys., 38, 683–701, https://doi.org/10.5194/angeo-38-683-2020, https://doi.org/10.5194/angeo-38-683-2020, 2020
Short summary
Short summary
We present a comprehensive statistical study of the response of the Earth's space environment in sheath regions prior to interplanetary coronal mass ejections. The inner magnetospheric wave activity is enhanced in sheath regions, and the sheaths cause significant changes to the outer radiation belt electron fluxes over short timescales. We also show that non-geoeffective sheaths can result in a significant response.
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.
Theodoros E. Sarris, Elsayed R. Talaat, Minna Palmroth, Iannis Dandouras, Errico Armandillo, Guram Kervalishvili, Stephan Buchert, Stylianos Tourgaidis, David M. Malaspina, Allison N. Jaynes, Nikolaos Paschalidis, John Sample, Jasper Halekas, Eelco Doornbos, Vaios Lappas, Therese Moretto Jørgensen, Claudia Stolle, Mark Clilverd, Qian Wu, Ingmar Sandberg, Panagiotis Pirnaris, and Anita Aikio
Geosci. Instrum. Method. Data Syst., 9, 153–191, https://doi.org/10.5194/gi-9-153-2020, https://doi.org/10.5194/gi-9-153-2020, 2020
Short summary
Short summary
Daedalus aims to measure the largely unexplored area between Eart's atmosphere and space, the Earth's
ignorosphere. Here, intriguing and complex processes govern the deposition and transport of energy. The aim is to quantify this energy by measuring effects caused by electrodynamic processes in this region. The concept is based on a mother satellite that carries a suite of instruments, along with smaller satellites carrying a subset of instruments that are released into the atmosphere.
Emilia Kilpua, Liisa Juusola, Maxime Grandin, Antti Kero, Stepan Dubyagin, Noora Partamies, Adnane Osmane, Harriet George, Milla Kalliokoski, Tero Raita, Timo Asikainen, and Minna Palmroth
Ann. Geophys., 38, 557–574, https://doi.org/10.5194/angeo-38-557-2020, https://doi.org/10.5194/angeo-38-557-2020, 2020
Short summary
Short summary
Coronal mass ejection sheaths and ejecta are key drivers of significant space weather storms, and they cause dramatic changes in radiation belt electron fluxes. Differences in precipitation of high-energy electrons from the belts to the upper atmosphere are thus expected. We investigate here differences in sheath- and ejecta-induced precipitation using the Finnish riometer (relative ionospheric opacity meter) chain.
Maxime Grandin, Markus Battarbee, Adnane Osmane, Urs Ganse, Yann Pfau-Kempf, Lucile Turc, Thiago Brito, Tuomas Koskela, Maxime Dubart, and Minna Palmroth
Ann. Geophys., 37, 791–806, https://doi.org/10.5194/angeo-37-791-2019, https://doi.org/10.5194/angeo-37-791-2019, 2019
Short summary
Short summary
When the terrestrial magnetic field is disturbed, particles from the near-Earth space can precipitate into the upper atmosphere. This work presents, for the first time, numerical simulations of proton precipitation in the energy range associated with the production of aurora (∼1–30 keV) using a global kinetic model of the near-Earth space: Vlasiator. We find that nightside proton precipitation can be regulated by the transition region between stretched and dipolar geomagnetic field lines.
Antti Lakka, Tuija I. Pulkkinen, Andrew P. Dimmock, Emilia Kilpua, Matti Ala-Lahti, Ilja Honkonen, Minna Palmroth, and Osku Raukunen
Ann. Geophys., 37, 561–579, https://doi.org/10.5194/angeo-37-561-2019, https://doi.org/10.5194/angeo-37-561-2019, 2019
Short summary
Short summary
We study how the Earth's space environment responds to two different amplitude interplanetary coronal mass ejection (ICME) events that occurred in 2012 and 2014 by using the GUMICS-4 global MHD model. We examine local and large-scale dynamics of the Earth's space environment and compare simulation results to in situ data. It is shown that during moderate driving simulation agrees well with the measurements; however, GMHD results should be interpreted cautiously during strong driving.
Liisa Juusola, Sanni Hoilijoki, Yann Pfau-Kempf, Urs Ganse, Riku Jarvinen, Markus Battarbee, Emilia Kilpua, Lucile Turc, and Minna Palmroth
Ann. Geophys., 36, 1183–1199, https://doi.org/10.5194/angeo-36-1183-2018, https://doi.org/10.5194/angeo-36-1183-2018, 2018
Short summary
Short summary
The solar wind interacts with the Earth’s magnetic field, forming a magnetosphere. On the night side solar wind stretches the magnetosphere into a long tail. A process called magnetic reconnection opens the magnetic field lines and reconnects them, accelerating particles to high energies. We study this in the magnetotail using a numerical simulation model of the Earth’s magnetosphere. We study the motion of the points where field lines reconnect and the fast flows driven by this process.
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
Short summary
Short summary
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
Short summary
Short summary
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.
Liisa Juusola, Yann Pfau-Kempf, Urs Ganse, Markus Battarbee, Thiago Brito, Maxime Grandin, Lucile Turc, and Minna Palmroth
Ann. Geophys., 36, 1027–1035, https://doi.org/10.5194/angeo-36-1027-2018, https://doi.org/10.5194/angeo-36-1027-2018, 2018
Short summary
Short summary
The Earth's magnetic field is shaped by the solar wind. On the dayside the field is compressed and on the nightside it is stretched as a long tail. The tail has been observed to occasionally undergo flapping motions, but the origin of these motions is not understood. We study the flapping using a numerical simulation of the near-Earth space. We present a possible explanation for how the flapping could be initiated by a passing disturbance and then maintained as a standing wave.
Matti M. Ala-Lahti, Emilia K. J. Kilpua, Andrew P. Dimmock, Adnane Osmane, Tuija Pulkkinen, and Jan Souček
Ann. Geophys., 36, 793–808, https://doi.org/10.5194/angeo-36-793-2018, https://doi.org/10.5194/angeo-36-793-2018, 2018
Short summary
Short summary
We present a comprehensive statistical analysis of mirror mode waves and the properties of their plasma surroundings in sheath regions driven by interplanetary coronal mass ejection (ICME) to deepen our understanding of these geo-effective plasma environments. The results imply that mirror modes are common structures in ICME sheaths and occur almost exclusively as dip-like structures and in mirror stable stable plasma.
Minna Palmroth, Sanni Hoilijoki, Liisa Juusola, Tuija I. Pulkkinen, Heli Hietala, Yann Pfau-Kempf, Urs Ganse, Sebastian von Alfthan, Rami Vainio, and Michael Hesse
Ann. Geophys., 35, 1269–1274, https://doi.org/10.5194/angeo-35-1269-2017, https://doi.org/10.5194/angeo-35-1269-2017, 2017
Short summary
Short summary
Much like solar flares, substorms occurring within the Earth's magnetic domain are explosive events that cause vivid auroral displays. A decades-long debate exists to explain the substorm onset. We devise a simulation encompassing the entire near-Earth space and demonstrate that detailed modelling of magnetic reconnection explains the central substorm observations. Our results help to understand the unpredictable substorm process, which will significantly improve space weather forecasts.
Antti Lakka, Tuija I. Pulkkinen, Andrew P. Dimmock, Adnane Osmane, Ilja Honkonen, Minna Palmroth, and Pekka Janhunen
Ann. Geophys., 35, 907–922, https://doi.org/10.5194/angeo-35-907-2017, https://doi.org/10.5194/angeo-35-907-2017, 2017
Short summary
Short summary
We studied the impact on global MHD simulations from different simulation initialisation methods. While the global MHD code used is GUMICS-4 we conclude that the results might be generalisable to other codes as well. It is found that different initialisation methods affect the dynamics of the Earth's space environment by creating differences in momentum transport several hours afterwards. These differences may even grow as a response to rapid solar wind condition changes.
Christina Chu, Hui Zhang, David Sibeck, Antonius Otto, QiuGang Zong, Nick Omidi, James P. McFadden, Dennis Fruehauff, and Vassilis Angelopoulos
Ann. Geophys., 35, 443–451, https://doi.org/10.5194/angeo-35-443-2017, https://doi.org/10.5194/angeo-35-443-2017, 2017
Short summary
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.
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
Yann Pfau-Kempf, Heli Hietala, Steve E. Milan, Liisa Juusola, Sanni Hoilijoki, Urs Ganse, Sebastian von Alfthan, and Minna Palmroth
Ann. Geophys., 34, 943–959, https://doi.org/10.5194/angeo-34-943-2016, https://doi.org/10.5194/angeo-34-943-2016, 2016
Short summary
Short summary
We have simulated the interaction of the solar wind – the charged particles and magnetic fields emitted by the Sun into space – with the magnetic field of the Earth. The solar wind flows supersonically and creates a shock when it encounters the obstacle formed by the geomagnetic field. We have identified a new chain of events which causes phenomena in the downstream region to eventually cause perturbations at the shock and even upstream. This is confirmed by ground and satellite observations.
Andrew P. Dimmock, Tuija I. Pulkkinen, Adnane Osmane, and Katariina Nykyri
Ann. Geophys., 34, 511–528, https://doi.org/10.5194/angeo-34-511-2016, https://doi.org/10.5194/angeo-34-511-2016, 2016
Short summary
Short summary
Ion densities measured on the dawn-side magnetosheath flank were higher than the dusk-flank. The asymmetry was measured close to the magnetopause, but it became more ambiguous in the central magnetosheath. We show that the asymmetry was at its maximum at the 2009 solar minimum (~ 20 %), but then decreased in the rising stage of the next solar cycle (< 5 %). These results could impact plasma transport processes which are dependent on local magnetopause conditions such as Kelvin Helmholtz Instability.
Erika Palmerio, Emilia K. J. Kilpua, and Neel P. Savani
Ann. Geophys., 34, 313–322, https://doi.org/10.5194/angeo-34-313-2016, https://doi.org/10.5194/angeo-34-313-2016, 2016
Short summary
Short summary
Coronal Mass Ejections (CMEs) are giant clouds of plasma and magnetic field that erupt from the Sun and travel though the solar wind. They can cause interplanetary shocks in the vicinity of Earth. We show in our paper that the region that follows CME-driven shocks, known as sheath region, can obtain a planar configuration of the magnetic field lines (planar magnetic structure, PMS) due to the compression resulting from the shock itself or from the draping of the magnetic field ahead of the CME.
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
Short summary
Short summary
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.
M. Myllys, E. Kilpua, and T. Pulkkinen
Ann. Geophys., 33, 845–855, https://doi.org/10.5194/angeo-33-845-2015, https://doi.org/10.5194/angeo-33-845-2015, 2015
P. T. Verronen, M. E. Andersson, A. Kero, C.-F. Enell, J. M. Wissing, E. R. Talaat, K. Kauristie, M. Palmroth, T. E. Sarris, and E. Armandillo
Ann. Geophys., 33, 381–394, https://doi.org/10.5194/angeo-33-381-2015, https://doi.org/10.5194/angeo-33-381-2015, 2015
Short summary
Short summary
Electron concentrations observed by EISCAT radars can be reasonable well represented using AIMOS v1.2 satellite-data-based ionization model and SIC D-region ion chemistry model. SIC-EISCAT difference varies from event to event, probably because the statistical nature of AIMOS ionization is not capturing all the spatio-temporal fine structure of electron precipitation. Below 90km, AIMOS overestimates electron ionization because of proton contamination of the satellite electron detectors.
K. Andréeová, L. Juusola, E. K. J. Kilpua, and H. E. J. Koskinen
Ann. Geophys., 32, 1293–1302, https://doi.org/10.5194/angeo-32-1293-2014, https://doi.org/10.5194/angeo-32-1293-2014, 2014
L. Turc, D. Fontaine, P. Savoini, and E. K. J. Kilpua
Ann. Geophys., 32, 1247–1261, https://doi.org/10.5194/angeo-32-1247-2014, https://doi.org/10.5194/angeo-32-1247-2014, 2014
L. Turc, D. Fontaine, P. Savoini, and E. K. J. Kilpua
Ann. Geophys., 32, 157–173, https://doi.org/10.5194/angeo-32-157-2014, https://doi.org/10.5194/angeo-32-157-2014, 2014
D. Pokhotelov, S. von Alfthan, Y. Kempf, R. Vainio, H. E. J. Koskinen, and M. Palmroth
Ann. Geophys., 31, 2207–2212, https://doi.org/10.5194/angeo-31-2207-2013, https://doi.org/10.5194/angeo-31-2207-2013, 2013
P. Kajdič, X. Blanco-Cano, N. Omidi, K. Meziane, C. T. Russell, J.-A. Sauvaud, I. Dandouras, and B. Lavraud
Ann. Geophys., 31, 2163–2178, https://doi.org/10.5194/angeo-31-2163-2013, https://doi.org/10.5194/angeo-31-2163-2013, 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
E. K. J. Kilpua, H. Hietala, H. E. J. Koskinen, D. Fontaine, and L. Turc
Ann. Geophys., 31, 1559–1567, https://doi.org/10.5194/angeo-31-1559-2013, https://doi.org/10.5194/angeo-31-1559-2013, 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
E. K. J. Kilpua, A. Isavnin, A. Vourlidas, H. E. J. Koskinen, and L. Rodriguez
Ann. Geophys., 31, 1251–1265, https://doi.org/10.5194/angeo-31-1251-2013, https://doi.org/10.5194/angeo-31-1251-2013, 2013
A. T. Aikio, T. Pitkänen, I. Honkonen, M. Palmroth, and O. Amm
Ann. Geophys., 31, 1021–1034, https://doi.org/10.5194/angeo-31-1021-2013, https://doi.org/10.5194/angeo-31-1021-2013, 2013
L. Turc, D. Fontaine, P. Savoini, H. Hietala, and E. K. J. Kilpua
Ann. Geophys., 31, 1011–1019, https://doi.org/10.5194/angeo-31-1011-2013, https://doi.org/10.5194/angeo-31-1011-2013, 2013
K. Andreeova, E. K. J. Kilpua, H. Hietala, H. E. J. Koskinen, A. Isavnin, and R. Vainio
Ann. Geophys., 31, 555–562, https://doi.org/10.5194/angeo-31-555-2013, https://doi.org/10.5194/angeo-31-555-2013, 2013
Related subject area
Subject: Magnetosphere & space plasma physics | Keywords: Bow shock and foreshock
Short large-amplitude magnetic structures (SLAMS) at Mercury observed by MESSENGER
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
Evidence of the nonstationarity of the terrestrial bow shock from multi-spacecraft observations: methodology, results, and quantitative comparison with particle-in-cell (PIC) simulations
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
Tomas Karlsson, Ferdinand Plaschke, Austin N. Glass, and Jim M. Raines
Ann. Geophys., 42, 117–130, https://doi.org/10.5194/angeo-42-117-2024, https://doi.org/10.5194/angeo-42-117-2024, 2024
Short summary
Short summary
The solar wind interacts with the planets in the solar system and creates a supersonic shock in front of them. The upstream region of this shock contains many complicated phenomena. One such phenomenon is small-scale structures of strong magnetic fields (SLAMS). These SLAMS have been observed at Earth and are important in determining the properties of space around the planet. Until now, SLAMS have not been observed at Mercury, but we show for the first time that SLAMS also exist there.
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.
Christian Mazelle and Bertrand Lembège
Ann. Geophys., 39, 571–598, https://doi.org/10.5194/angeo-39-571-2021, https://doi.org/10.5194/angeo-39-571-2021, 2021
Short summary
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.
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
Short summary
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
Short summary
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.
Cited articles
Archer, M. O., Horbury, T. S., Eastwood, J. P., Weygand, J. M., and Yeoman,
T. K.: Magnetospheric response to magnetosheath pressure pulses: A
low-pass filter effect, J. Geophys. Res.-Space, 118, 5454–5466,
https://doi.org/10.1002/jgra.50519,
2013. a
Bale, S. D., Balikhin, M. A., Horbury, T. S., Krasnoselskikh, V. V.,
Kucharek, H., Möbius, E., Walker, S. N., Balogh, A., Burgess,
D., Lembège, B., Lucek, E. A., Scholer, M., Schwartz, S. J.,
and Thomsen, M. F.: Quasi-perpendicular Shock Structure and Processes,
Space Sci. Rev., 118, 161–203, https://doi.org/10.1007/s11214-005-3827-0, 2005. a
Blanco-Cano, X., Omidi, N., and Russell, C. T.: Macrostructure of
collisionless bow shocks: 2. ULF waves in the foreshock and magnetosheath,
J. Geophys. Res., 111, A10205, https://doi.org/10.1029/2005JA011421, 2006. a
Blanco-Cano, X., Omidi, N., and Russell, C. T.: Global hybrid
simulations: Foreshock waves and cavitons under radial interplanetary
magnetic field geometry, J. Geophys. Res., 114, A01216,
https://doi.org/10.1029/2008JA013406, 2009. a, b, c
Blanco-Cano, X., Kajdič, P., Omidi, N., and Russell, C. T.:
Foreshock cavitons for different interplanetary magnetic field geometries:
Simulations and observations, J. Geophys. Res., 116, A09101,
https://doi.org/10.1029/2010JA016413, 2011. a
Burgess, D.: Cyclic behavior at quasi-parallel collisionless shocks, Geophys.
Res. Lett., 16, 345–348, https://doi.org/10.1029/GL016i005p00345, 1989. a
Burgess, D. and Scholer, M.: Microphysics of Quasi-parallel Shocks in
Collisionless Plasmas, Space Sci. Rev., 178, 513–533,
https://doi.org/10.1007/s11214-013-9969-6, 2013. a
Burgess, D., Lucek, E. A., Scholer, M., Bale, S. D., Balikhin,
M. A.,
Balogh, A., Horbury, T. S., Krasnoselskikh, V. V., Kucharek, H.,
Lembège, B., Möbius, E., Schwartz, S. J., Thomsen, M. F., and
Walker, S. N.: Quasi-parallel Shock Structure and Processes, Space Sci.
Rev., 118, 205–222, https://doi.org/10.1007/s11214-005-3832-3, 2005. a
Caprioli, D. and Spitkovsky, A.: Cosmic-Ray-induced Filamentation
Instability in Collisionless Shocks, Astrophys. J. Lett., 765, L20,
https://doi.org/10.1088/2041-8205/765/1/L20, 2013. a
Childs, H., Brugger, E., Whitlock, B., Meredith, J., Ahern, S., Pugmire, D., Biagas, K., Miller, M., Harrison, C., Weber, G. H., Krishnan, H., Fogal, T., Sanderson, A., Garth, C., Bethel, E. W., Camp, D., Rübel, O.,
Durant, M., Favre, J. M., and Navrátil, P.:
VisIt: An End-User Tool For Visualizing and Analyzing Very Large Data, in: High Performance Visualization–Enabling Extreme-Scale Scientific
Insight, Chapman & Hall/CRC, 357–372, 2012. a
Collinson, G., Sibeck, D., Omidi, N., Grebowsky, J., Halekas, J.,
Mitchell, D., Espley, J., Zhang, T., Persson, M., Futaana, Y., and
Jakosky, B.: Spontaneous hot flow anomalies at Mars and Venus, J.
Geophys. Res.-Space, 122, 9910–9923, https://doi.org/10.1002/2017JA024196, 2017. a
Daldorff, L. K. S., Tóth, G., Gombosi, T. I., Lapenta, G.,
Amaya,
J., Markidis, S., and Brackbill, J. U.: Two-way coupling of a global
Hall magnetohydrodynamics model with a local implicit particle-in-cell
model, J. Comput. Phys., 268, 236–254, https://doi.org/10.1016/j.jcp.2014.03.009,
2014. a
Eastwood, J. P., Balogh, A., Lucek, E. A., Mazelle, C., and Dandouras, I.:
Quasi-monochromatic ULF foreshock waves as observed by the four-spacecraft
Cluster mission: 1. Statistical properties, J. Geophys. Res.-Space, 110,
A11219, https://doi.org/10.1029/2004JA010617, 2005. a, b
Eastwood, J. P., Hietala, H., Toth, G., Phan, T. D., and Fujimoto, M.: What
Controls the Structure and Dynamics of Earth's Magnetosphere?, Space Sci.
Rev., 188, 251–286, https://doi.org/10.1007/s11214-014-0050-x, 2015. a, b
Facskó, G., Németh, Z., Erdos, G., Kis, A., and Dandouras, I.: A
global study of hot flow anomalies using Cluster multi-spacecraft
measurements, Ann. Geophys., 27, 2057–2076,
https://doi.org/10.5194/angeo-27-2057-2009, 2009. a
Hannuksela, O. and the Vlasiator team:
Analysator: python analysis toolkit, available at: https://github.com/fmihpc/analysator/ (last access: 19 July 2018), 2018. a
Hao, Y., Lembege, B., Lu, Q., and Guo, F.: Formation of downstream high-speed
jets by
a rippled nonstationary quasi-parallel shock: 2-D hybrid simulations, J.
Geophys. Res.-Space, 121, 2080–2094, https://doi.org/10.1002/2015JA021419,
2016. a
Hao, Y., Gao, X., Lu, Q., Huang, C., Wang, R., and Wang, S.: Reformation of
rippled quasi parallel shocks: 2-D hybrid simulations, J. Geophys. Res.-Space, 122, 6385–6396, https://doi.org/10.1002/2017JA024234,
2017. a
Hietala, H., Laitinen, T. V., Andréeová, K., Vainio, R.,
Vaivads, A., Palmroth, M., Pulkkinen, T. I., Koskinen, H. E. J.,
Lucek, E. A., and Rème, H.: Supermagnetosonic Jets behind a
Collisionless Quasiparallel Shock, Phys. Rev. Lett., 103, 245001,
https://doi.org/10.1103/PhysRevLett.103.245001, 2009. a
Hoilijoki, S., Palmroth, M., Walsh, B. M., Pfau-Kempf, Y., von
Alfthan, S., Ganse, U., Hannuksela, O., and Vainio, R.: Mirror modes
in the Earth's magnetosheath: Results from a global hybrid-Vlasov
simulation, J. Geophys. Res.-Space, 121, 4191–4204,
https://doi.org/10.1002/2015JA022026, 2016. a
Hoilijoki, S., Ganse, U., Sibeck, D., Cassak, P., Fear, R., Battarbee, M.,
Blanco-Cano, X., Dimmock, A. P., Kilpua, E., Jarvinen, R., Juusola, L.,
Pfau-Kempf, Y., Turc, L., and Palmroth, M.: Comparison of FTEs and dayside
reconnection with and without a sunward tilt of the southward interplanetary
magnetic field, J. Geophys. Res.-Space, under review, 2018. a
Hoppe, M. M., Russell, C. T., Frank, L. A., Eastman, T. E., and
Greenstadt, E. W.: Upstream hydromagnetic waves and their association with
backstreaming ion populations – ISEE 1 and 2 observations, J. Geophys. Res.,
86, 4471–4492, https://doi.org/10.1029/JA086iA06p04471, 1981. a, b
Kajdič, P., Blanco-Cano, X., Omidi, N., and Russell, C. T.: Analysis of
waves
surrounding foreshock cavitons, AIP Conf. Proc., 1216, 479–482,
https://doi.org/10.1063/1.3395907, 2010. a, b
Kajdič, P., Blanco-Cano, X., Omidi, N., and Russell, C. T.:
Multi-spacecraft study of foreshock cavitons upstream of the quasi-parallel
bow shock, Planet. Space Sci., 59, 705–714,
https://doi.org/10.1016/j.pss.2011.02.005, 2011. a, b
Kajdič, P., Blanco-Cano, X., Omidi, N., Meziane, K., Russell, C. T.,
Sauvaud, J.-A., Dandouras, I., and Lavraud, B.: Statistical study of
foreshock cavitons, Ann. Geophys., 31, 2163–2178,
https://doi.org/10.5194/angeo-31-2163-2013, 2013. a, b, c, d
Katırcıoǧlu, F. T., Kaymaz, Z., Sibeck, D. G., and Dandouras, I.:
Magnetosheath cavities: case studies using Cluster observations, Ann.
Geophys., 27, 3765–3780, https://doi.org/10.5194/angeo-27-3765-2009, 2009. a, b, c, d
Kempf, Y., Pokhotelov, D., Gutynska, O., Wilson III, L. B., Walsh, B. M.,
von Alfthan, S., Hannuksela, O., Sibeck, D. G., and Palmroth, M.: Ion
distributions in the Earth's foreshock: Hybrid-Vlasov simulation and THEMIS
observations, J. Geophys. Res.-Space, 120, 3684–3701,
https://doi.org/10.1002/2014JA020519, 2015. a
Mazelle, C., Meziane, K., LeQuéau, D., Wilber, M., Eastwood, J.,
Rème,
H., Sauvaud, J., Bosqued, J., Dandouras, I., McCarthy, M., Kistler, L.,
Klecker, B., Korth, A., Bavassano-Cattaneo, M., Pallocchia, G., Lundin, R.,
and Balogh, A.: Production of gyrating ions from nonlinear wave–particle
interaction upstream from the Earth's bow shock: A case study from
Cluster-CIS, Planet. Space Sci., 51, 785–795,
https://doi.org/10.1016/j.pss.2003.05.002, 2003. a
Meziane, K., Mazelle, C., Lin, R. P., LeQuéau, D., Larson, D. E., Parks,
G. K., and Lepping, R. P.: Three-dimensional observations of gyrating ion
distributions far upstream from the Earth's bow shock and their association
with low-frequency waves, J. Geophys. Res.-Space, 106, 5731–5742,
https://doi.org/10.1029/2000JA900079, 2001. a
Omidi, N.: Formation of cavities in the foreshock, in: Turbulence and
Nonlinear Processes in Astrophysical Plasmas, edited by: Shaikh, D. and
Zank, G. P., Vol. 932 of AIP Conf. Proc., 181–190,
https://doi.org/10.1063/1.2778962, 2007. a
Omidi, N. and Sibeck, D. G.: Formation of hot flow anomalies and
solitary
shocks, J. Geophys. Res.-Space, 112, A01203, https://doi.org/10.1029/2006JA011663,
2007. a
Omidi, N., Blanco-Cano, X., and Russell, C. T.: Macrostructure of
collisionless bow shocks: 1. Scale lengths, J. Geophys. Res.-Space, 110,
A12212, https://doi.org/10.1029/2005JA011169, 2005. a, b
Omidi, N., Sibeck, D., Blanco-Cano, X., Rojas-Castillo, D., Turner,
D., Zhang, H., and Kajdič, P.: Dynamics of the foreshock
compressional boundary and its connection to foreshock cavities, J. Geophys.
Res.-Space, 118, 823–831, https://doi.org/10.1002/jgra.50146, 2013. a, b, c
Omidi, N., Sibeck, D., Gutynska, O., and Trattner, K. J.: Magnetosheath
filamentary structures formed by ion acceleration at the quasi-parallel bow
shock, J. Geophys. Res.-Space, 119, 2593–2604, https://doi.org/10.1002/2013JA019587,
2014a. a
Omidi, N., Zhang, H., Chu, C., Sibeck, D., and Turner, D.: Parametric
dependencies of spontaneous hot flow anomalies, J. Geophys. Res.-Space, 119,
9823–9833, https://doi.org/10.1002/2014JA020382,
2014b. a
Omidi, N., Berchem, J., Sibeck, D., and Zhang, H.: Impacts of
spontaneous hot flow anomalies on the magnetosheath and magnetopause, J.
Geophys. Res.-Space, 121, 3155–3169, https://doi.org/10.1002/2015JA022170, 2016. a, b, c, d
Omidi, N., Collinson, G., and Sibeck, D.: Structure and Properties of
the Foreshock at Venus, J. Geophys. Res.-Space, 122, 10275–10286,
https://doi.org/10.1002/2017JA024180, 2017. a
Palmroth, M. and the Vlasiator team:
Vlasiator: hybrid-Vlasov simulation code, Github repository, available at:
https://github.com/fmihpc/vlasiator/ (last access: 19 July 2018),
2018. a
Palmroth, M., Archer, M., Vainio, R., Hietala, H., Pfau-Kempf, Y.,
Hoilijoki, S., Hannuksela, O., Ganse, U., Sandroos, A., Alfthan,
S. v., and Eastwood, J. P.: ULF foreshock under radial IMF: THEMIS
observations and global kinetic simulation Vlasiator results compared, J.
Geophys. Res.-Space, 120, 8782–8798, https://doi.org/10.1002/2015JA021526, 2015. a, b, c, d
Palmroth, M., Hietala, H., Plaschke, F., Archer, M., Karlsson, T.,
Blanco-Cano, X., Sibeck, D., Kajdič, P., Ganse, U., Pfau-Kempf, Y.,
Battarbee, M., and Turc, L.: Magnetosheath jet properties and evolution as
determined by a global hybrid-Vlasov simulation, Ann. Geophys. Discuss.,
https://doi.org/10.5194/angeo-2018-20, in review, 2018. a, b
Pfau-Kempf, Y.: Vlasiator – From local to global magnetospheric
hybrid-Vlasov simulations, PhD thesis, University of Helsinki,
available at: http://urn.fi/URN:ISBN:978-952-336-001-3 (last access:
1 December 2016), 2016. a
Pfau-Kempf, Y., Battarbee, M., Ganse, U., Hoilijoki, S., Turc, L., von
Alfthan,
S., Vainio, R., and Palmroth, M.: On the importance of spatial and velocity
resolution in the hybrid-Vlasov modeling of collisionless shocks, Front. Phys., 6, 44, https://doi.org/10.3389/fphy.2018.00044, 2018.
a, b
Sandroos, A.:
VLSV: file format and tools, Github repository, available at:
https://github.com/fmihpc/vlsv/ (last access: 19 July 2018), 2018. a
Scholer, M., Fujimoto, M., and Kucharek, H.: Two-dimensional simulations of
supercritical quasi-parallel shocks: Upstream waves, downstream waves, and
shock re-formation, J. Geophys. Res.-Space, 98, 18971–18984,
https://doi.org/10.1029/93JA01647,
1993. a
Schwartz, S. J.: Hot flow anomalies near the Earth's bow shock, Adv.
Space
Res., 15, 107–116, https://doi.org/10.1016/0273-1177(95)00025-A, 1995. a, b
Schwartz, S. J. and Burgess, D.: Quasi-parallel shocks – A patchwork of
three-dimensional structures, Geophys. Res. Lett., 18, 373–376,
https://doi.org/10.1029/91GL00138, 1991. a, b
Schwartz, S. J., Chaloner, C. P., Christiansen, P. J., Coates, A. J., Hall,
D. S., Johnstone, A. D., Gough, M. P., Norris, A. J., Rijnbeek, R. P.,
Southwood, D. J., and Woolliscroft, L. J. C.: An active current sheet in the
solar wind, Nature, 318, 269–271, https://doi.org/10.1038/318269a0, 1985. a, b
Sibeck, D. G., Borodkova, N. L., Schwartz, S. J., Owen, C. J.,
Kessel, R., Kokubun, S., Lepping, R. P., Lin, R., Liou, K.,
Lühr, H., McEntire, R. W., Meng, C.-I., Mukai, T., Nemecek, Z.,
Parks, G., Phan, T. D., Romanov, S. A., Safrankova, J., Sauvaud,
J.-A., Singer, H. J., Solovyev, S. I., Szabo, A., Takahashi, K.,
Williams, D. J., Yumoto, K., and Zastenker, G. N.: Comprehensive study
of the magnetospheric response to a hot flow anomaly, J. Geophys. Res.-Space, 104, 4577–4594, https://doi.org/10.1029/1998JA900021, 1999. a
von Alfthan, S., Pokhotelov, D., Kempf, Y., Hoilijoki, S., Honkonen, I.,
Sandroos, A., and Palmroth, M.: Vlasiator: First global hybrid-Vlasov
simulations of Earth's foreshock and magnetosheath, J. Atmos. Sol.-Terr.
Phy., 120, 24–35, https://doi.org/10.1016/j.jastp.2014.08.012,
2014. a, b
Wilson, L. B.: Low Frequency Waves at and Upstream of Collisionless Shocks,
269–291, John Wiley & Sons, Inc., https://doi.org/10.1002/9781119055006.ch16, 2016. a
Winterhalter, D. and Kivelson, M. G.: Observations of the Earth's bow shock
under high Mach number/high plasma beta solar wind conditions, Geophys. Res.
Lett., 15, 1161–1164, https://doi.org/10.1029/GL015i010p01161, 1988. a
Zhang, H., Sibeck, D. G., Zong, Q.-G., Omidi, N., Turner, D., and Clausen, L.
B. N.: Spontaneous hot flow anomalies at quasi-parallel shocks: 1.
Observations, J. Geophys. Res.-Space, 118, 3357–3363,
https://doi.org/10.1002/jgra.50376, 2013. a, b, c
Zhao, L. L., Zong, Q. G., Zhang, H., and Wang, S.: Case and statistical
studies
on the evolution of hot flow anomalies, J. Geophys. Res.-Space, 120,
6332–6346, https://doi.org/10.1002/2014JA020862, 2015. a
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.
We use the Vlasiator code to study the characteristics of transient structures that exist in the...
