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1. First Radar -- CubeSat Transionospheric HF Propagation Observations: Suomi 100 Satellite and EISCAT HF Facility

Author

Kallio, Esa, Kero, Antti, Harri, Ari-Matti, Kestilä, Antti, Aikio, Anita, Fontell, Mathias, Jarvinen, Riku, Kauristie, Kirsti, Knuuttila, Olli, Koskimaa, Petri, Loyala, Jauaries, Lukkari, Juha-Matti, Modabberian, Amin, Niittyniemi, Joonas, Rynö, Jouni, Vanhamäki, Heikki, and Varberg, Erik

Subjects
Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Radio waves provide a useful diagnostic tool to investigate the properties of the ionosphere because the ionosphere affects the transmission and properties of High Frequency (HF) electromagnetic waves. We have conducted a transionospheric HF-propagation research campaign with a nanosatellite on a low-Earth polar orbit and the EISCAT HF transmitter facility in Troms{\o}, Norway, in December 2020. In the active measurement, the EISCAT HF facility transmitted sinusoidal 7.953 MHz signal which was received with the HEARER radio spectrometer onboard 1 Unit (size: 10 cm x 10 cm x 10 cm) Suomi 100 space weather nanosatellite. Data analysis showed that the EISCAT HF signal was detected with the satellite's radio spectrometer when the satellite was the closest to the heater along its orbit. Part of the observed variations seen in the signal was identified to be related to the heater's antenna pattern and to the transmitted pulse shapes. Other observed variations can be related to the spatial and temporal variations of the ionosphere and its different responses to the used transmission frequencies and to the transmitted O- and X-wave modes. Some trends in the observed signal may also be associated to changes in the properties of ionospheric plasma resulting from the heater's electromagnetic wave energy. This paper is, to authors' best knowledge, the first observation of this kind of "self-absorption" measured from the transionospheric signal path from a powerful radio source on the ground to the satellite-borne receiver., Comment: 27 pages, 10 images

Published
2022
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2. Auroral imaging with combined Suomi 100 nanosatellite and ground-based observations: A case study

Author

Kallio, Esa, Harri, Ari-Matti, Knuuttila, Olli, Jarvinen, Riku, Kauristie, Kirsti, Kestilä, Antti, Kivekäs, Jarmo, Koskimaa, Petri, Lukkari, Juha-Matti, Partamies, Noora, Rynö, Jouni, and Syrjäsuo, Mikko

Subjects
Physics - Space Physics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Auroras can be regarded as the most fascinating manifestation of space weather and they are continuously observed by ground-based and, nowadays more and more, also by space-based measurements. Investigations of auroras and geospace comprise the main research goals of the Suomi 100 nanosatellite, the first Finnish space research satellite, which has been measuring the Earth's ionosphere since its launch on Dec. 3, 2018. In this work, we present a case study where the satellite's camera observations of an aurora over Northern Europe are combined with ground-based observations of the same event. The analyzed image is, to the authors' best knowledge, the first auroral image ever taken by a cubesat. Our data analysis shows that a satellite vantage point provides complementary, novel information of such phenomena. The 3D auroral location reconstruction of the analyzed auroral event demonstrates how information from a 2D image can be used to provide location information of auroras under study. The location modelling also suggests that the Earth's limb direction, which was the case in the analyzed image, is an ideal direction to observe faint auroras. Although imaging on a small satellite has some large disadvantages compared with ground-based imaging (the camera cannot be repaired, a fast moving spinning satellite), the data analysis and modelling demonstrate how even a small 1-Unit (size: 10 cm x 10 cm x 10 cm) CubeSat and its camera, build using cheap commercial off-the-shelf components, can open new possibilities for auroral research, especially, when its measurements are combined with ground-based observations., Comment: Accepted manuscript 34 pages, 17 figures

Published
2022
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3. Planetary Magnetic Field Control of Ion Escape from Weakly Magnetized Planets

Author

Egan, Hilary, Jarvinen, Riku, Ma, Yingjuan, and Brain, David

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Intrinsic magnetic fields have long been thought to shield planets from atmospheric erosion via stellar winds; however, the influence of the plasma environment on atmospheric escape is complex. Here we study the influence of a weak intrinsic dipolar planetary magnetic field on the plasma environment and subsequent ion escape from a Mars sized planet in a global three-dimensional hybrid simulation. We find that increasing the strength of a planet's magnetic field enhances ion escape until the magnetic dipole's standoff distance reaches the induced magnetosphere boundary. After this point increasing the planetary magnetic field begins to inhibit ion escape. This reflects a balance between shielding of the southern hemisphere from ``misaligned" ion pickup forces and trapping of escaping ions by an equatorial plasmasphere. Thus, the planetary magnetic field associated with the peak ion escape rate is critically dependent on the stellar wind pressure. Where possible we have fit power laws for the variation of fundamental parameters (escape rate, escape power, polar cap opening angle and effective interaction area) with magnetic field, and assessed upper and lower limits for the relationships., Comment: Accepted to MNRAS. 17 pages, 10 figures

Published
2019
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4. Stellar Influence on Heavy Ion Escape from Unmagnetized Exoplanets

Author

Egan, Hilary, Jarvinen, Riku, and Brain, David

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Planetary habitability is in part determined by the atmospheric evolution of a planet; one key component of such evolution is escape of heavy ions to space. Ion loss processes are sensitive to the plasma environment of the planet, dictated by the stellar wind and stellar radiation. These conditions are likely to vary from what we observe in our own solar system when considering a planet in the habitable zone around an M-dwarf. Here we use a hybrid global plasma model to perform a systematic study of the changing plasma environment and ion escape as a function of stellar input conditions, which are designed to mimic those of potentially habitable planets orbiting M-dwarfs. We begin with a nominal case of a solar wind experienced at Mars today, and incrementally modify the interplanetary magnetic field orientation and strength, dynamic pressure, and Extreme Ultraviolet input. We find that both ion loss morphology and overall rates vary significantly, and in cases where the stellar wind pressure was increased, the ion loss began to be diffusion or production limited with roughly half of all produced ions being lost. This limit implies that extreme care must be taken when extrapolating loss processes observed in the solar system to extreme environments., Comment: Accepted to MNRAS. 10 pages, 3 figures, 2 tables

Published
2019
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7. The Energetic Oxygen Ion Beams in the Martian Magnetotail Current Sheets: Hints From the Comparisons Between Two Types of Current Sheets.

Author

Zhang, Chi, Rong, Zhaojin, Li, Xinzhou, Fränz, Markus, Nilsson, Hans, Jarvinen, Riku, Persson, Moa, Futaana, Yoshifumi, Dong, Chuanfei, Yamauchi, Masatoshi, Gao, Jiawei, Zhou, Yijia, Wang, Lei, Shi, Zhen, Wei, Yong, He, Fei, Holmström, Mats, and Barabash, Stas

Subjects
CURRENT sheets, ION beams, SOLAR wind, MARTIAN atmosphere, MAGNETIC structure, OXYGEN, ELECTRIC fields
Abstract

Using data from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, we explore the plasma properties of Martian magnetotail current sheets (CS), to further understand the solar wind interaction with Mars and ion escape. There are some CS exhibit energetic oxygen ions that show narrow beam structures in the energy spectrum, which primarily occurs in the hemisphere where the solar wind electric field (Esw) is directed away from the planet. On average, these CS have a higher escaping flux than that of the CS without energetic oxygen ion beams, suggesting different roles in ion escape. The CS with energetic oxygen ion beams exhibits different proton and electron properties to the CS without energetic oxygen ion beams, indicating their different origins. Our analysis suggests that the CS with energetic oxygen ion beams may result from the interaction between the penetrated solar wind and localized oxygen ion plumes. Plain Language Summary: Ion escape into space, driven by solar wind interactions with Mars, plays a pivotal role in the evolution of the Martian atmosphere. An important escape channel of planetary oxygen ions is the current sheet in the nightside magnetotail. Yet, our existing understanding of plasma characteristics within this magnetic structure remains quite limited. Based on the MAVEN observations, we find the current sheets can be categorized into two distinct types according to the energy distribution patterns of oxygen ions: one is with the appearance of energetic oxygen ions with narrow beam structure, the other one is not. On average, the current sheets with energetic oxygen ion beams have a higher escaping flux than those without, suggesting different roles in ion escape. Furthermore, the two types of current sheets exhibit markedly distinct plasma properties, indicating that they have different origins. Here we suggest that the current sheet with energetic oxygen ion beams arise from the interaction between the penetrated solar wind and localized oxygen ion plumes. Key Points: Martian magnetotail current sheets occasionally exhibit energetic oxygen ions that show beam structures in the energy spectrumThe current sheets with energetic oxygen ion beam usually have a higher escaping flux than those withoutPlasma properties in current sheets differ significantly differences between those with and without energetic oxygen ion beams [ABSTRACT FROM AUTHOR]

Published
2024
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8. BepiColombo Science Investigations During Cruise and Flybys at the Earth, Venus and Mercury

Author

Mangano, Valeria, Dósa, Melinda, Fränz, Markus, Milillo, Anna, Oliveira, Joana S., Lee, Yeon Joo, McKenna-Lawlor, Susan, Grassi, Davide, Heyner, Daniel, Kozyrev, Alexander S., Peron, Roberto, Helbert, Jörn, Besse, Sebastien, de la Fuente, Sara, Montagnon, Elsa, Zender, Joe, Volwerk, Martin, Chaufray, Jean-Yves, Slavin, James A., Krüger, Harald, Maturilli, Alessandro, Cornet, Thomas, Iwai, Kazumasa, Miyoshi, Yoshizumi, Lucente, Marco, Massetti, Stefano, Schmidt, Carl A., Dong, Chuanfei, Quarati, Francesco, Hirai, Takayuki, Varsani, Ali, Belyaev, Denis, Zhong, Jun, Kilpua, Emilia K. J., Jackson, Bernard V., Odstrcil, Dusan, Plaschke, Ferdinand, Vainio, Rami, Jarvinen, Riku, Ivanovski, Stavro Lambrov, Madár, Ákos, Erdős, Géza, Plainaki, Christina, Alberti, Tommaso, Aizawa, Sae, Benkhoff, Johannes, Murakami, Go, Quemerais, Eric, Hiesinger, Harald, Mitrofanov, Igor G., Iess, Luciano, Santoli, Francesco, Orsini, Stefano, Lichtenegger, Herbert, Laky, Gunther, Barabash, Stas, Moissl, Richard, Huovelin, Juhani, Kasaba, Yasumasa, Saito, Yoshifumi, Kobayashi, Masanori, and Baumjohann, Wolfgang

Published
2021
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9. Auroral imaging with combined Suomi 100 nanosatellite and ground‐based observations: A case study

Author

Kallio, Esa, primary, Harri, Ari‐Matti, additional, Knuuttila, Olli, additional, Jarvinen, Riku, additional, Kauristie, Kirsti, additional, Kestilä, Antti, additional, Kivekäs, Jarmo, additional, Koskimaa, Petri, additional, Lukkari, Juha‐Matti, additional, Partamies, Noora, additional, Rynö, Jouni, additional, and Syrjäsuo, Mikko, additional

Published
2023
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12. Solar Orbiter Model-Data Comparison in Venus' Induced Magnetotail

Author

Stergiopoulou, Katerina, Jarvinen, Riku, Andrews, David J., Edberg, Niklas J. T., Dimmock, Andrew P., Kallio, Esa, Persson, Moa, and Khotyaintsev, Yuri V.

Subjects
Fusion, plasma och rymdfysik, Fusion, Plasma and Space Physics
Abstract

We investigate the structure of the Venusian magnetotail utilizing magnetic field and electron density measurements that cover a wide range of distances from the planet, from the first two Solar Orbiter Venus flybys. We examine the magnetic field components along the spacecraft trajectory up to 80 Venus radii down the tail. Even though the magnetic field behavior differs considerably between the two cases, we see extended electron density enhancements covering distances greater than ∼20 RV in both flybys. We compare the magnetic field measurements with a global hybrid model of the induced magnetosphere and magnetotail of Venus, to examine to what degree the observations can be understood with the simulation. The model upstream conditions are stationary and the solution encloses a large volume of 83 RV × 60 RV × 60 RV in which we look for spatial magnetic field and plasma variations. We rotate the simulation solution to describe different stationary upstream IMF clock angle cases with a 10° step and find the clock angle for which the agreement between observations and model is maximized along Solar Orbiter's trajectory in 1-min steps. We find that in both flybys there is better agreement with the observations when we rotate the model for some intervals, while there are parts that cannot be well reproduced by the model irrespective of how we vary the IMF clock angle, suggesting the presence of non-stationary features in the Venus-solar wind interaction not accounted for in the hybrid model.

Published
2023

13. Radar—CubeSat Transionospheric HF Propagation Observations: Suomi 100 Satellite and EISCAT HF Facility

Author

Kallio, Esa, primary, Kero, Antti, additional, Harri, Ari‐Matti, additional, Kestilä, Antti, additional, Aikio, Anita, additional, Fontell, Mathias, additional, Jarvinen, Riku, additional, Kauristie, Kirsti, additional, Knuuttila, Olli, additional, Koskimaa, Petri, additional, Loyala, Jauaries, additional, Lukkari, Juha‐Matti, additional, Modabberian, Amin, additional, Niittyniemi, Joonas, additional, Rynö, Jouni, additional, Vanhamäki, Heikki, additional, and Varberg, Erik, additional

Published
2022
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20. Oxygen ion escape at Mars in a hybrid model: High energy and low energy ions

Author

Kallio, Esa, Liu, Kaijun, Jarvinen, Riku, Pohjola, Valter, and Janhunen, Pekka

Subjects
Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2009.05.015 Byline: Esa Kallio (a)(b), Kaijun Liu (a), Riku Jarvinen (a), Valter Pohjola (a), Pekka Janhunen (a) Keywords: Mars; Planetary ionospheres; Planetary magnetospheres; Numerical modelling; Hybrid model Abstract: We have studied the escape and energization of several O.sup.+ populations and an O.sub.2.sup.+ population at Mars by using a hybrid model. The quasi-neutral hybrid model, HYB-Mars model, included five oxygen ion populations making it possible to distinguish photoions from oxygen ions originating from charge exchange processes and from the ionosphere. We have identified two high-energy ion components and one low-energy ion component of oxygen. They have different spatial and energy distributions near Mars. The two high-energy oxygen ion components, consisting of a high-energy 'beam' and a high-energy 'halo', have different origins. (1) The high-energy (>[approximately equal to]100eV) 'beam' of O.sup.+ and O.sub.2.sup.+ ions are originating from the ionosphere. These ions form a highly asymmetric spatial distribution of escaping oxygen ions with respect to the direction of the convective electric field in the solar wind. (2) The high-energy (>[approximately equal to]100eV) 'halo' component contains O.sup.+ ions which are formed from the oxygen neutral exosphere by extreme ultraviolet radiation (EUV) and by charge exchange processes. These energetic halo ions can be found all around Mars. (3) The low energy O.sup.+ and O.sub.2.sup.+ ions ( The existence of the low- and the high-energy oxygen components is in agreement with recent in situ plasma measurements made by the ASPERA-3 instrument on the Mars Express mission. The analysis of the escaping oxygen ions suggests that the global energization of escaping planetary ions in the martian tail is controlled by the convective electric field. Author Affiliation: (a) Finnish Meteorological Institute, Helsinki, Finland (b) University of Helsinki, Department of Physics, Helsinki, Finland Article History: Received 15 November 2008; Revised 31 March 2009; Accepted 11 May 2009

Published
2010

26. Ionosphere research with a nanosatellite’s radio wave spectrometer

Author

Kallio, Esa, primary, Harri, Ari-Matti, additional, Aikio, Anita, additional, Alho, Arno, additional, Fontell, Mathias, additional, Jarvinen, Riku, additional, Kauristie, Kirsti, additional, Kero, Antti, additional, Kestilä, Antti, additional, Koskimaa, Petri, additional, Lukkari, Juha-Matti, additional, Knuuttila, Olli, additional, Loyala, Jauaries, additional, Niittyniemi, Joonas, additional, Norberg, Johannes, additional, Rynö, Jouni, additional, Turunen, Esa, additional, and Vanhamäki, Heikki, additional

Published
2020
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28. Fast plasma sheet flows and X line motion in the Earth's magnetotail

Author

Juusola, Liisa, Hoilijoki, Sanni, Pfau-Kempf, Yann, Ganse, Urs, Jarvinen, Riku, Battarbee, Markus, Kilpua, Emilia, Turc, Lucile, Palmroth, Minna, Finnish Meteorological Institute, University of Helsinki, Tuija Pulkkinen Group, Department of Electronics and Nanoengineering, Aalto-yliopisto, and Aalto University

Subjects
Physics::Space Physics
Abstract

Fast plasma flows produced as outflow jets from reconnection sites or X lines are a key feature of the dynamics in the Earth's magnetosphere. We have used a polar plane simulation of the hybrid-Vlasov model Vlasiator, driven by steady southward interplanetary magnetic field and fast solar wind, to study fast plasma sheet ion flows and related magnetic field structures in the Earth's magnetotail. In the simulation, lobe reconnection starts to produce fast flows after the increasing pressure in the lobes has caused the plasma sheet to thin sufficiently. The characteristics of the earthward and tailward fast flows and embedded magnetic field structures produced by multi-point tail reconnection are in general agreement with spacecraft measurements reported in the literature. The structuring of the flows is caused by internal processes: interactions between major X points determine the earthward or tailward direction of the flow, while interactions between minor X points, associated with leading edges of magnetic islands carried by the flow, induce local minima and maxima in the flow speed. Earthward moving flows are stopped and diverted duskward in an oscillatory (bouncing) manner at the transition region between tail-like and dipolar magnetic fields. Increasing and decreasing dynamic pressure of the flows causes the transition region to shift earthward and tailward, respectively. The leading edge of the train of earthward flow bursts is associated with an earthward propagating dipolarization front, while the leading edge of the train of tailward flow bursts is associated with a tailward propagating plasmoid. The impact of the dipolarization front with the dipole field causes magnetic field variations in the Pi2 range. Major X points can move either earthward or tailward, although tailward motion is more common. They are generally not advected by the ambient flow. Instead, their velocity is better described by local parameters, such that an X point moves in the direction of increasing reconnection electric field strength. Our results indicate that ion kinetics might be sufficient to describe the behavior of plasma sheet bulk ion flows produced by tail reconnection in global near-Earth simulations.

Published
2018

32. Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation

Author

Blanco-Cano, Xochitl, primary, Battarbee, Markus, additional, Turc, Lucile, additional, Dimmock, Andrew P., additional, Kilpua, Emilia K. J., additional, Hoilijoki, Sanni, additional, Ganse, Urs, additional, Sibeck, David G., additional, Cassak, Paul A., additional, Fear, Robert C., additional, Jarvinen, Riku, additional, Juusola, Liisa, additional, Pfau-Kempf, Yann, additional, Vainio, Rami, additional, and Palmroth, Minna, additional

Published
2018
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34. Supplementary material to "Cavitons and spontaneous hot flow anomalies in a hybrid-Vlasov global magnetospheric simulation"

Author

Blanco-Cano, Xochitl, primary, Battarbee, Markus, additional, Turc, Lucile, additional, Dimmock, Andrew P., additional, Kilpua, Emilia K. J., additional, Hoilijoki, Sanni, additional, Ganse, Urs, additional, Sibeck, David G., additional, Cassak, Paul A., additional, Fear, Robert C., additional, Jarvinen, Riku, additional, Juusola, Liisa, additional, Pfau-Kempf, Yann, additional, Vainio, Rami, additional, and Palmroth, Minna, additional

Published
2018
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35. Solar Cycle Dynamic of the Martian Induced Magnetosphere. Planetary Ions Acceleration Zones and Escape

Author

Fedorov, Andrei, Barbash, Stas, Modolo, Ronan, Jarvinen, Riku, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Finnish Meteorological Institute (FMI), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics::Space Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Earth and Planetary Astrophysics
Abstract

International audience; This work presents a massive statistical analysis of the ion flows in the Martian induced magnetosphere. We performed this analysis usingMars Express ion mass spectrometer data taken during 2008 - 20014 time interval. This data allows to makean enhanced study of the induced magnetosphere variations as a response of the solar activity level. Since Mars Express hasno onboard magnetometer, we used the hybrid models of the Martian plasma environment to get a proper frame tomake an adequate statistics of the magnetospheric response. In this paper we present a spatial distribution of theplanetary plasma propoerties in the planetary wake as well as the ionsospheric escape as a function of the solar activity.

Published
2015

36. Energization of Oxygen Ions at Mars: Comparison of a Global Hybrid Model to In Situ Observations

Author

Jarvinen, Riku, Brain, Dave, Fedorov, Andrei, Holmström, Mats, Modolo, Ronan, Finnish Meteorological Institute (FMI), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Swedish Institute of Space Physics [Kiruna] (IRF), HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics::Space Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Earth and Planetary Astrophysics
Abstract

International audience; We study the energization of planetary oxygen ions escaping from the atmosphere of Mars in a global hybrid model for the Mars-solar wind interaction. In the hybrid approach ions are modelled as particles moving under the Lorentz force and electrons are a charge-neutralizing fluid. Thus, electric and magnetic field are self-consistently coupled with ion dynamics. We identify ion energization regions in the induced magnetosphere of Mars in the model. Further, we study electric and magnetic fields associated with the ion acceleration processes. Finally, we compare our simulation results to in situ particle and magnetic field observations on the MAVEN and Mars Express missions.

Published
2015

37. Energization of planetary pickup ions in the solar system

Author

Jarvinen, Riku, Kallio, Esa, Esa Kallio Group, Department of Radio Science and Engineering, Aalto-yliopisto, and Aalto University

Subjects
education, pickup ions, space plasma, space weather, solar wind
Published
2014

38. A case study of proton precipitation at Mars:Mars Express observations and hybrid simulations

Author

Dieval, Catherine, Kallio, Esa, Barabash, Stas, Stenberg, Gabriella, Nilsson, Hans, Futaana, Yoshifumi, Holmstrom, Mats, Fedorov, Andrei, Frahm, Rudy, Jarvinen, Riku, and Brain, David

Subjects
Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics
Abstract

Using the data from the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) experiment on board Mars Express and hybrid simulations, we have investigated the entry of protons into the Martian induced magnetosphere. We discuss one orbit on the dayside with observations of significant proton fluxes at altitudes down to 260 km on 27 February 2004. The protons observed below the induced magnetosphere boundary at an altitude of less than 700 km have energies of a few keV, travel downward, and precipitate onto the atmosphere. The measured energy flux and particle flux are 10^8–10^9 eV cm^−2 s^−1 and 10^5–10^6 H^+ cm^−2 s^−1, respectively. The proton precipitation occurs because the Martian magnetosheath is small with respect to the heated proton gyroradius in the subsolar region. The data suggest that the precipitation is not permanent but may occur when there are transient increases in the magnetosheath proton temperature. The higher-energy protons penetrate deeper because of their larger gyroradii. The proton entry into the induced magnetosphere is simulated using a hybrid code. A simulation using a fast solar wind as input can reproduce the high energies of the observed precipitating protons. The model shows that the precipitating protons originate from both the solar wind and the planetary exosphere. The precipitation extends over a few thousand kilometers along the orbit of the spacecraft. The proton precipitation does not necessarily correlate with the crustal magnetic anomalies.

Published
2012

39. The ion foreshock of Venus in a global hybrid simulation.

Author

Jarvinen, Riku, Alho, Markku, Kallio, Esa, and Pulkkinen, Tuija

Subjects
*HYBRID computer simulation, *INTERPLANETARY magnetic fields, *ION mobility, *PLASMA waves, *ORIGIN of planets, *SOLAR wind
Abstract

We study the ion foreshock of Venus using a 3-dimensional global hybrid simulation. The ion foreshock forms in the upstream region ahead of the Venusian quasi-parallel bow shock. The interplanetary magnetic field is connected to the bow shock upstream of the quasi-parallel shock and the angle between the shock normal and the magnetic field is smaller than ~45 degrees. This configuration allows the reflection of solar wind ions back upstream leading to the formation of the ion foreshock. Backstreaming ions are a source of free energy for excitation of plasma waves. In a hybrid simulation, ions of solar wind and planetary origin are treated as particles moving under the Lorentz force, while electrons form a charge-neutralizing fluid. Ion velocity distributions evolve according to the model calculation and are self-consistently coupled with the evolution of the magnetic field. In this simulation study, we analyze the morphology and wave modes of the Venusian ion foreshock. [ABSTRACT FROM AUTHOR]

Published
2019

41. Ionosphere and arctic research with Suomi100 nanosatellite.

Author

Kallio, Esa, Harri, Ari-Matti, Aikio, Anita, Alho, Markku, Fontell, Mathias, Jarvinen, Riku, Kauristie, Kirsti, Kestilä, Antti, Turunen, Esa, Vanhamäki, Heikki, Norberg, Johannes, Koskimaa, Petri, Alho, Arno, Knuuttila, Olli, and Rynö, Jouni

Published
2019

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