Articles | Volume 36, issue 5
https://doi.org/10.5194/angeo-36-1171-2018
© 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-36-1171-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
07 Sep 2018
Regular paper |
| 07 Sep 2018
| 07 Sep 2018
Magnetosheath jet properties and evolution as determined by a global hybrid-Vlasov simulation
Minna Palmroth
CORRESPONDING AUTHOR
Department of Physics, University of Helsinki, Helsinki, Finland
Space and Earth Observation Centre, Finnish Meteorological Institute, Helsinki, Finland
Heli Hietala
Department of Physics and Astronomy, University of Turku, Turku, Finland
Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, USA
Ferdinand Plaschke
Institute of Physics, University of Graz, Graz, Austria
Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Martin Archer
The Blackett Laboratory, Imperial College London, London, UK
School of Physics and Astronomy, Queen Mary University of London, London, UK
Tomas Karlsson
School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
Xóchitl Blanco-Cano
Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico
David Sibeck
Code 674, NASA Goddard Space Flight Center, Greenbelt, MD, USA
Primož Kajdič
Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico
Urs Ganse
Department of Physics, University of Helsinki, Helsinki, Finland
Yann Pfau-Kempf
Department of Physics, University of Helsinki, Helsinki, Finland
Markus Battarbee
Department of Physics, University of Helsinki, Helsinki, Finland
Lucile Turc
Department of Physics, University of Helsinki, Helsinki, Finland
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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
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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
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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.
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Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-7, https://doi.org/10.5194/angeo-2024-7, 2024
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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.
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
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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.
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
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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.
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
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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.
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
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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
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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
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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
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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
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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
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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.
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
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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.
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
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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.
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
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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
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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
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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
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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
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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
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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
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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
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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.
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.
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
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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.
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
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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
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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.
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
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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.
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
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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.
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
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
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
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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.
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
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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
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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.
Adrian Pöppelwerth, Georg Glebe, Johannes Z. D. Mieth, Florian Koller, Tomas Karlsson, Zoltán Vörös, and Ferdinand Plaschke
Ann. Geophys., 42, 271–284, https://doi.org/10.5194/angeo-42-271-2024, https://doi.org/10.5194/angeo-42-271-2024, 2024
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In the magnetosheath, a near-Earth region of space, we observe increases in plasma velocity and density, so-called jets. As they propagate towards Earth, jets interact with the ambient plasma. We study this interaction with three spacecraft simultaneously to infer their sizes. While previous studies have investigated their size almost exclusively statistically, we demonstrate a new method of determining the sizes of individual jets.
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
Preprint under review for ANGEO
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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.
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
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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.
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
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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.
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
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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
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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.
Leonard Schulz, Karl-Heinz Glassmeier, Ferdinand Plaschke, Simon Toepfer, and Uwe Motschmann
Ann. Geophys., 41, 449–463, https://doi.org/10.5194/angeo-41-449-2023, https://doi.org/10.5194/angeo-41-449-2023, 2023
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The upper detection limit in reciprocal space, the spatial Nyquist limit, is derived for arbitrary spatial dimensions for the wave telescope analysis technique. This is important as future space plasma missions will incorporate larger numbers of spacecraft (>4). Our findings are a key element in planning the spatial distribution of future multi-point spacecraft missions. The wave telescope is a multi-dimensional power spectrum estimator; hence, this can be applied to other fields of research.
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.
Henriette Trollvik, Tomas Karlsson, and Savvas Raptis
Ann. Geophys., 41, 327–337, https://doi.org/10.5194/angeo-41-327-2023, https://doi.org/10.5194/angeo-41-327-2023, 2023
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The solar wind is in a plasma state and can exhibit a range of phenomena like waves and instabilities. One observed phenomenon in the solar wind is magnetic holes (MHs). They are localized depressions in the magnetic field. We studied the motion of MHs using the multispacecraft ESA Cluster mission. We derived their velocities in the solar wind frame and found that both linear and rotational MHs are convected with the solar wind.
Tomas Karlsson, Henriette Trollvik, Savvas Raptis, Hans Nilsson, and Hadi Madanian
Ann. Geophys., 40, 687–699, https://doi.org/10.5194/angeo-40-687-2022, https://doi.org/10.5194/angeo-40-687-2022, 2022
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Magnetic holes are curious localized dropouts of magnetic field strength in the solar wind (the flow of ionized gas continuously streaming out from the sun). In this paper we show that these magnetic holes can cross the bow shock (where the solar wind brake down to subsonic velocity) and enter the region close to Earth’s magnetosphere. These structures may therefore represent a new type of non-uniform solar wind–magnetosphere interaction.
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
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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.
Martin O. Archer, Cara L. Waters, Shafiat Dewan, Simon Foster, and Antonio Portas
Geosci. Commun., 5, 119–123, https://doi.org/10.5194/gc-5-119-2022, https://doi.org/10.5194/gc-5-119-2022, 2022
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Educational research highlights that improved careers education is needed to increase participation in science, technology, engineering, and mathematics (STEM). Current UK careers resources in the space sector, however, are found to perhaps not best reflect the diversity of roles present and may in fact perpetuate misconceptions about the usefulness of science. We, therefore, compile a more diverse set of space-related jobs, which will be used in the development of a new space careers resource.
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
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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.
Martin Volwerk, Beatriz Sánchez-Cano, Daniel Heyner, Sae Aizawa, Nicolas André, Ali Varsani, Johannes Mieth, Stefano Orsini, Wolfgang Baumjohann, David Fischer, Yoshifumi Futaana, Richard Harrison, Harald Jeszenszky, Iwai Kazumasa, Gunter Laky, Herbert Lichtenegger, Anna Milillo, Yoshizumi Miyoshi, Rumi Nakamura, Ferdinand Plaschke, Ingo Richter, Sebastián Rojas Mata, Yoshifumi Saito, Daniel Schmid, Daikou Shiota, and Cyril Simon Wedlund
Ann. Geophys., 39, 811–831, https://doi.org/10.5194/angeo-39-811-2021, https://doi.org/10.5194/angeo-39-811-2021, 2021
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On 15 October 2020, BepiColombo used Venus as a gravity assist to change its orbit to reach Mercury in late 2021. During this passage of Venus, the spacecraft entered into Venus's magnetotail at a distance of 70 Venus radii from the planet. We have studied the magnetic field and plasma data and find that Venus's magnetotail is highly active. This is caused by strong activity in the solar wind, where just before the flyby a coronal mass ejection interacted with the magnetophere of Venus.
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
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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.
Daniel Schmid, Yasuhito Narita, Ferdinand Plaschke, Martin Volwerk, Rumi Nakamura, and Wolfgang Baumjohann
Ann. Geophys., 39, 563–570, https://doi.org/10.5194/angeo-39-563-2021, https://doi.org/10.5194/angeo-39-563-2021, 2021
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In this work we present the first analytical magnetosheath plasma flow model for the space environment around Mercury. The proposed model is relatively simple to implement and provides the possibility to trace the flow lines inside the Hermean magnetosheath. It can help to determine the the local plasma conditions of a spacecraft in the magnetosheath exclusively on the basis of the upstream solar wind parameters.
Martin O. Archer, Jennifer DeWitt, Charlotte Thorley, and Olivia Keenan
Geosci. Commun., 4, 147–168, https://doi.org/10.5194/gc-4-147-2021, https://doi.org/10.5194/gc-4-147-2021, 2021
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We explore how best to support school students to experience undertaking research-level physics by evaluating provision in the PRiSE framework of
research in schoolsprojects. These experiences are received by students and teachers much more positively than typical forms of outreach. The intensive support offered is deemed necessary, with all elements appearing equally important. We suggest the framework could be adopted at other institutions applied to their own areas of scientific research.
Martin O. Archer and Jennifer DeWitt
Geosci. Commun., 4, 169–188, https://doi.org/10.5194/gc-4-169-2021, https://doi.org/10.5194/gc-4-169-2021, 2021
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The impacts upon a diverse range of students, teachers, and schools from participating in a programme of protracted university-mentored projects based on cutting-edge physics research are assessed. The lasting impacts on confidence, skills, aspirations, and practice suggest that similar
research in schoolsinitiatives may have a role to play in aiding the increased uptake and diversity of physics/STEM in higher education as well as meaningfully enhancing the STEM environment within schools.
Martin O. Archer
Geosci. Commun., 4, 189–208, https://doi.org/10.5194/gc-4-189-2021, https://doi.org/10.5194/gc-4-189-2021, 2021
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An evaluation of the accessibility and equity of a programme of independent research projects shows that, with the right support from both teachers and active researchers, schools' ability to succeed at undertaking cutting-edge research appears independent of typical societal inequalities.
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
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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.
Martin Volwerk, David Mautner, Cyril Simon Wedlund, Charlotte Goetz, Ferdinand Plaschke, Tomas Karlsson, Daniel Schmid, Diana Rojas-Castillo, Owen W. Roberts, and Ali Varsani
Ann. Geophys., 39, 239–253, https://doi.org/10.5194/angeo-39-239-2021, https://doi.org/10.5194/angeo-39-239-2021, 2021
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The magnetic field in the solar wind is not constant but varies in direction and strength. One of these variations shows a strong local reduction of the magnetic field strength and is called a magnetic hole. These holes are usually an indication that there is, or has been, a temperature difference in the plasma of the solar wind, with the temperature along the magnetic field lower than perpendicular. The MMS spacecraft data have been used to study the characteristics of these holes near Earth.
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
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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.
Martin O. Archer, Natt Day, and Sarah Barnes
Geosci. Commun., 4, 57–67, https://doi.org/10.5194/gc-4-57-2021, https://doi.org/10.5194/gc-4-57-2021, 2021
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We show that integrating evaluation tools both before and after a drop-in engagement activity enables the demonstration of change and, thus, short-term impact. In our case, young families who listened to space sounds exhibited changed language and conceptions about space in their graffiti wall responses afterwards, exemplifying the power of sound in science communication. We suggest that evaluation tools be adopted both before and after drop-in activities in general.
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
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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.
Yasuhito Narita, Ferdinand Plaschke, Werner Magnes, David Fischer, and Daniel Schmid
Geosci. Instrum. Method. Data Syst., 10, 13–24, https://doi.org/10.5194/gi-10-13-2021, https://doi.org/10.5194/gi-10-13-2021, 2021
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The systematic error of calibrated fluxgate magnetometer data is studied for a spinning spacecraft. The major error comes from the offset uncertainty when the ambient magnetic field is low, while the error represents the combination of non-orthogonality, misalignment to spacecraft reference direction, and gain when the ambient field is high. The results are useful in developing future high-precision magnetometers and an error estimate in scientific studies using magnetometer data.
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
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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
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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.
Ovidiu Dragoş Constantinescu, Hans-Ulrich Auster, Magda Delva, Olaf Hillenmaier, Werner Magnes, and Ferdinand Plaschke
Geosci. Instrum. Method. Data Syst., 9, 451–469, https://doi.org/10.5194/gi-9-451-2020, https://doi.org/10.5194/gi-9-451-2020, 2020
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We propose a gradiometer-based technique for cleaning multi-sensor magnetic field data acquired on board spacecraft. The technique takes advantage on the fact that the maximum-variance direction of many AC disturbances on board spacecraft does not change over time. We apply the proposed technique to the SOSMAG instrument on board GeoKompsat-2A. We analyse the performance and limitations of the technique and discuss in detail how various disturbances are removed.
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
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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.
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
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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.
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
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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.
Daniel Schmid, Ferdinand Plaschke, Yasuhito Narita, Daniel Heyner, Johannes Z. D. Mieth, Brian J. Anderson, Martin Volwerk, Ayako Matsuoka, and Wolfgang Baumjohann
Ann. Geophys., 38, 823–832, https://doi.org/10.5194/angeo-38-823-2020, https://doi.org/10.5194/angeo-38-823-2020, 2020
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Recently, the two-spacecraft mission BepiColombo was launched to explore Mercury. To measure the magnetic field precisely, in-flight calibration of the magnetometer offset is needed. Usually, the offset is evaluated from magnetic field observations in the solar wind. Since one of the spacecraft will remain within Mercury's magnetic environment, we examine an alternative calibration method. We show that this method is applicable and may be a valuable tool to determine the offset accurately.
Martin O. Archer
Geosci. Commun., 3, 147–166, https://doi.org/10.5194/gc-3-147-2020, https://doi.org/10.5194/gc-3-147-2020, 2020
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The Space Sound Effects Short Film Festival integrated near-Earth space environment research into culture through independent film. By running a film festival challenging filmmakers to incorporate the sounds of space, creative works were produced which have gone on to be screened at numerous established film festivals and events internationally. These events introduced non-science audiences to this area of research which affects their everyday lives, having several unanticipated impacts on them.
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
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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
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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
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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
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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.
Ferdinand Plaschke, Maria Jernej, Heli Hietala, and Laura Vuorinen
Ann. Geophys., 38, 287–296, https://doi.org/10.5194/angeo-38-287-2020, https://doi.org/10.5194/angeo-38-287-2020, 2020
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Jets of solar-wind plasma commonly hit the Earth's magnetosphere. Using data from the four Magnetospheric Multiscale (MMS) spacecraft, we show statistically that within jets the magnetic field is more aligned with the plasma flow direction than outside of these jets. Our study confirms prior simulation results, but it also shows that the average effect is moderate. The jets' magnetic field is important with respect to their impact on space weather.
Martin Volwerk, Charlotte Goetz, Ferdinand Plaschke, Tomas Karlsson, Daniel Heyner, and Brian Anderson
Ann. Geophys., 38, 51–60, https://doi.org/10.5194/angeo-38-51-2020, https://doi.org/10.5194/angeo-38-51-2020, 2020
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The magnetic field that is carried by the solar wind slowly decreases in strength as it moves further from the Sun. However, there are sometimes localized decreases in the magnetic field strength, called magnetic holes. These are small structures where the magnetic field strength decreases to less than 50 % of the surroundings and the plasma density increases. This paper presents a statistical study of the behaviour of these holes between Mercury and Venus using MESSENGER data.
Ferdinand Plaschke
Geosci. Instrum. Method. Data Syst., 8, 285–291, https://doi.org/10.5194/gi-8-285-2019, https://doi.org/10.5194/gi-8-285-2019, 2019
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Measuring the magnetic field onboard spacecraft requires regular in-flight calibration activities. Among those, determining the output of magnetometers under vanishing ambient magnetic fields, the so-called magnetometer offsets, is essential. Typically, characteristic rotations in solar wind magnetic fields are used to obtain these offsets. This paper addresses the question of how many solar wind data are needed to reach certain accuracy levels in offset determination.
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
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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.
Laura Vuorinen, Heli Hietala, and Ferdinand Plaschke
Ann. Geophys., 37, 689–697, https://doi.org/10.5194/angeo-37-689-2019, https://doi.org/10.5194/angeo-37-689-2019, 2019
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Before the solar wind encounters the Earth's magnetic field, it is first slowed down and deflected by the Earth's bow shock. We find that downstream of the bow shock regions where the shock normal and the solar wind magnetic field are almost parallel and the shock is more rippled, plasma jets with high earthward velocities are observed significantly more often than elsewhere downstream of the shock. Our results help us forecast the occurrence of these jets and their effects on Earth.
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
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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.
Ferdinand Plaschke, Hans-Ulrich Auster, David Fischer, Karl-Heinz Fornaçon, Werner Magnes, Ingo Richter, Dragos Constantinescu, and Yasuhito Narita
Geosci. Instrum. Method. Data Syst., 8, 63–76, https://doi.org/10.5194/gi-8-63-2019, https://doi.org/10.5194/gi-8-63-2019, 2019
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Raw output of spacecraft magnetometers has to be converted into meaningful units and coordinate systems before it is usable for scientific applications. This conversion is defined by 12 calibration parameters, 8 of which are more easily determined in flight if the spacecraft is spinning. We present theory and advanced algorithms to determine these eight parameters. They take into account the physical magnetometer and spacecraft behavior, making them superior to previously published algorithms.
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
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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.
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.
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
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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.
Ferdinand Plaschke and Heli Hietala
Ann. Geophys., 36, 695–703, https://doi.org/10.5194/angeo-36-695-2018, https://doi.org/10.5194/angeo-36-695-2018, 2018
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Fast jets of solar wind particles drive through a slower environment in the magnetosheath, located sunward of the region dominated by the Earth’s magnetic field. THEMIS multi-spacecraft observations show that jets push ambient particles out of their way. These particles flow around the faster jets into the jets’ wake. Thereby, jets stir the magnetosheath, changing the properties of this key region whose particles and magnetic fields can directly interact with the Earth’s magnetic field.
Tomas Karlsson, Ferdinand Plaschke, Heli Hietala, Martin Archer, Xóchitl Blanco-Cano, Primož Kajdič, Per-Arne Lindqvist, Göran Marklund, and Daniel J. Gershman
Ann. Geophys., 36, 655–677, https://doi.org/10.5194/angeo-36-655-2018, https://doi.org/10.5194/angeo-36-655-2018, 2018
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We have studied fast plasma jets outside of Earth’s magnetic environment. Such jets are small-scale structures with a limited lifetime, which may be important in determining the properties of the near-Earth space environment, due to their concentrated kinetic energy. We have used data from the NASA Magnetospheric MultiScale (MMS) satellites to study their properties in detail, to understand how these jets are formed. We have found evidence that there are at least two different types of jets.
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
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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.
Sudong Xiao, Tielong Zhang, Guoqiang Wang, Martin Volwerk, Yasong Ge, Daniel Schmid, Rumi Nakamura, Wolfgang Baumjohann, and Ferdinand Plaschke
Ann. Geophys., 35, 1015–1022, https://doi.org/10.5194/angeo-35-1015-2017, https://doi.org/10.5194/angeo-35-1015-2017, 2017
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
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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.
Elisabet Liljeblad and Tomas Karlsson
Ann. Geophys., 35, 879–884, https://doi.org/10.5194/angeo-35-879-2017, https://doi.org/10.5194/angeo-35-879-2017, 2017
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MESSENGER magnetic field data from the magnetosphere of Mercury have been investigated to identify ultra-low-frequency (ULF) waves. ULF waves in the Kelvin–Helmholtz (KH) wave frequency range are frequently observed in the magnetosphere. These ULF waves often have similar characteristics to previously identified, likely KH-driven ULF waves, indicating that ULF waves in a specific frequency band can be used as a detection tool for KH waves on Mercury.
Rikard Slapak, Maria Hamrin, Timo Pitkänen, Masatoshi Yamauchi, Hans Nilsson, Tomas Karlsson, and Audrey Schillings
Ann. Geophys., 35, 869–877, https://doi.org/10.5194/angeo-35-869-2017, https://doi.org/10.5194/angeo-35-869-2017, 2017
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The ion total transports in the near-Earth plasma sheet have been investigated and quantified. Specifically, the net O+ transport is about 1024 s−1 in the earthward direction, which is 1 order of magnitude smaller than the typical O+ ionospheric outflows, strongly indicating that most outflow will eventually escape, leading to significant atmospheric loss. The study also shows that low-velocity flows (< 100 km s−1) dominate the mass transport in the near-Earth plasma sheet.
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
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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.
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.
Martin Volwerk, Daniel Schmid, Bruce T. Tsurutani, Magda Delva, Ferdinand Plaschke, Yasuhito Narita, Tielong Zhang, and Karl-Heinz Glassmeier
Ann. Geophys., 34, 1099–1108, https://doi.org/10.5194/angeo-34-1099-2016, https://doi.org/10.5194/angeo-34-1099-2016, 2016
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The behaviour of mirror mode waves in Venus's magnetosheath is investigated for solar minimum and maximum conditions. It is shown that the total observational rate of these waves does not change much; however, the distribution over the magnetosheath is significantly different, as well as the growth and decay of the waves during these different solar activity conditions.
David Fischer, Werner Magnes, Christian Hagen, Ivan Dors, Mark W. Chutter, Jerry Needell, Roy B. Torbert, Olivier Le Contel, Robert J. Strangeway, Gernot Kubin, Aris Valavanoglou, Ferdinand Plaschke, Rumi Nakamura, Laurent Mirioni, Christopher T. Russell, Hannes K. Leinweber, Kenneth R. Bromund, Guan Le, Lawrence Kepko, Brian J. Anderson, James A. Slavin, and Wolfgang Baumjohann
Geosci. Instrum. Method. Data Syst., 5, 521–530, https://doi.org/10.5194/gi-5-521-2016, https://doi.org/10.5194/gi-5-521-2016, 2016
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This paper describes frequency and timing calibration, modeling and data processing and calibration for MMS magnetometers, resulting in a merged search choil and fluxgate data product.
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
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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.
Ferdinand Plaschke and Yasuhito Narita
Ann. Geophys., 34, 759–766, https://doi.org/10.5194/angeo-34-759-2016, https://doi.org/10.5194/angeo-34-759-2016, 2016
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Spacecraft-mounted magnetic field instruments (magnetometers) need to be routinely calibrated. This involves determining the magnetometer outputs in vanishing ambient magnetic fields, the so-called offsets. We introduce and test a new method to determine these offsets with high accuracy, the mirror mode method, which is complementary to existing methods. The mirror mode method should be highly beneficial to current and future magnetic field observations near Earth, other planets, and comets.
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.
M. O. Archer, T. S. Horbury, P. Brown, J. P. Eastwood, T. M. Oddy, B. J. Whiteside, and J. G. Sample
Ann. Geophys., 33, 725–735, https://doi.org/10.5194/angeo-33-725-2015, https://doi.org/10.5194/angeo-33-725-2015, 2015
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The first in-flight results from a new design of miniaturised magnetometer (MAGIC - MAGnetometer from Imperial College), aboard the first CINEMA (Cubesat for Ions, Neutrals, Electrons and MAgnetic fields) spacecraft in low Earth orbit, are presented. Not only can this sensor be used for determining attitude, but it is also able to detect the extremely small (20-40 nT) magnetic field signatures of field-aligned currents at the auroral oval. Thus, there are science capabilities with such sensors.
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
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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.
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
H. Gunell, G. Stenberg Wieser, M. Mella, R. Maggiolo, H. Nilsson, F. Darrouzet, M. Hamrin, T. Karlsson, N. Brenning, J. De Keyser, M. André, and I. Dandouras
Ann. Geophys., 32, 991–1009, https://doi.org/10.5194/angeo-32-991-2014, https://doi.org/10.5194/angeo-32-991-2014, 2014
D. Schmid, M. Volwerk, F. Plaschke, Z. Vörös, T. L. Zhang, W. Baumjohann, and Y. Narita
Ann. Geophys., 32, 651–657, https://doi.org/10.5194/angeo-32-651-2014, https://doi.org/10.5194/angeo-32-651-2014, 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
R. Nakamura, F. Plaschke, R. Teubenbacher, L. Giner, W. Baumjohann, W. Magnes, M. Steller, R. B. Torbert, H. Vaith, M. Chutter, K.-H. Fornaçon, K.-H. Glassmeier, and C. Carr
Geosci. Instrum. Method. Data Syst., 3, 1–11, https://doi.org/10.5194/gi-3-1-2014, https://doi.org/10.5194/gi-3-1-2014, 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. 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
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
C. Nabert, K.-H. Glassmeier, and F. Plaschke
Ann. Geophys., 31, 419–437, https://doi.org/10.5194/angeo-31-419-2013, https://doi.org/10.5194/angeo-31-419-2013, 2013
M. O. Archer and T. S. Horbury
Ann. Geophys., 31, 319–331, https://doi.org/10.5194/angeo-31-319-2013, https://doi.org/10.5194/angeo-31-319-2013, 2013
Related subject area
Subject: Magnetosphere & space plasma physics | Keywords: Magnetosheath
Proton plasma asymmetries between the convective-electric-field hemispheres of Venus' dayside magnetosheath
Scale size estimation and flow pattern recognition around a magnetosheath jet
Scalar-potential mapping of the steady-state magnetosheath model
Local bow shock environment during magnetosheath jet formation: results from a hybrid-Vlasov simulation
Statistical distribution of mirror-mode-like structures in the magnetosheaths of unmagnetized planets – Part 2: Venus as observed by the Venus Express spacecraft
Magnetosheath plasma flow model around Mercury
Magnetosheath jet evolution as a function of lifetime: global hybrid-Vlasov simulations compared to MMS observations
Asymmetries in the Earth's dayside magnetosheath: results from global hybrid-Vlasov simulations
On the alignment of velocity and magnetic fields within magnetosheath jets
Jets in the magnetosheath: IMF control of where they occur
Sebastián Rojas Mata, Gabriella Stenberg Wieser, Tielong Zhang, and Yoshifumi Futaana
Ann. Geophys., 42, 419–429, https://doi.org/10.5194/angeo-42-419-2024, https://doi.org/10.5194/angeo-42-419-2024, 2024
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The Sun ejects a stream of charged particles into space that have to flow around planets like Venus. We quantify how this flow varies with spatial location using spacecraft measurements of the particles and magnetic field taken over several years. We find that this flow is connected to interactions with the heavier charged particles that originate from Venus’ upper atmosphere. These interactions are not unique to Venus, so we compare our results to similar studies at Mars.
Adrian Pöppelwerth, Georg Glebe, Johannes Z. D. Mieth, Florian Koller, Tomas Karlsson, Zoltán Vörös, and Ferdinand Plaschke
Ann. Geophys., 42, 271–284, https://doi.org/10.5194/angeo-42-271-2024, https://doi.org/10.5194/angeo-42-271-2024, 2024
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In the magnetosheath, a near-Earth region of space, we observe increases in plasma velocity and density, so-called jets. As they propagate towards Earth, jets interact with the ambient plasma. We study this interaction with three spacecraft simultaneously to infer their sizes. While previous studies have investigated their size almost exclusively statistically, we demonstrate a new method of determining the sizes of individual jets.
Yasuhito Narita, Daniel Schmid, and Simon Toepfer
Ann. Geophys., 42, 79–89, https://doi.org/10.5194/angeo-42-79-2024, https://doi.org/10.5194/angeo-42-79-2024, 2024
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The magnetosheath is a transition layer surrounding the planetary magnetosphere. We develop an algorithm to compute the plasma flow velocity and magnetic field for a more general shape of magnetosheath using the concept of potential field and suitable coordinate transformation. Application to the empirical Earth magnetosheath region is shown in the paper. The developed algorithm is useful when interpreting the spacecraft data or simulation of the planetary magnetosheath region.
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
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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.
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.
Daniel Schmid, Yasuhito Narita, Ferdinand Plaschke, Martin Volwerk, Rumi Nakamura, and Wolfgang Baumjohann
Ann. Geophys., 39, 563–570, https://doi.org/10.5194/angeo-39-563-2021, https://doi.org/10.5194/angeo-39-563-2021, 2021
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In this work we present the first analytical magnetosheath plasma flow model for the space environment around Mercury. The proposed model is relatively simple to implement and provides the possibility to trace the flow lines inside the Hermean magnetosheath. It can help to determine the the local plasma conditions of a spacecraft in the magnetosheath exclusively on the basis of the upstream solar wind parameters.
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
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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.
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
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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.
Ferdinand Plaschke, Maria Jernej, Heli Hietala, and Laura Vuorinen
Ann. Geophys., 38, 287–296, https://doi.org/10.5194/angeo-38-287-2020, https://doi.org/10.5194/angeo-38-287-2020, 2020
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Jets of solar-wind plasma commonly hit the Earth's magnetosphere. Using data from the four Magnetospheric Multiscale (MMS) spacecraft, we show statistically that within jets the magnetic field is more aligned with the plasma flow direction than outside of these jets. Our study confirms prior simulation results, but it also shows that the average effect is moderate. The jets' magnetic field is important with respect to their impact on space weather.
Laura Vuorinen, Heli Hietala, and Ferdinand Plaschke
Ann. Geophys., 37, 689–697, https://doi.org/10.5194/angeo-37-689-2019, https://doi.org/10.5194/angeo-37-689-2019, 2019
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Before the solar wind encounters the Earth's magnetic field, it is first slowed down and deflected by the Earth's bow shock. We find that downstream of the bow shock regions where the shock normal and the solar wind magnetic field are almost parallel and the shock is more rippled, plasma jets with high earthward velocities are observed significantly more often than elsewhere downstream of the shock. Our results help us forecast the occurrence of these jets and their effects on Earth.
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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.
Magnetosheath jets are high-velocity plasma structures that are commonly observed within the...
