Articles | Volume 32, issue 2
https://doi.org/10.5194/angeo-32-83-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/angeo-32-83-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Regular paper
| 
12 Feb 2014
Regular paper |
| 12 Feb 2014
Ion drift simulation of sudden appearance of sub-keV structured ions in the inner magnetosphere
M. Yamauchi
Swedish Institute of Space Physics (IRF), Box 812, 98128 Kiruna, Sweden
Y. Ebihara
Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
H. Nilsson
Swedish Institute of Space Physics (IRF), Box 812, 98128 Kiruna, Sweden
I. Dandouras
CNRS, Institut de Recherche en Astrophysique et Planétologie (IRAP), BP 44346, 31028, Toulouse cedex 4, France
University of Toulouse, UPS-OMP, IRAP, Toulouse, France
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Terrestrial ion transport and total escape are synthesized, with stress on the high-latitude polar region and the inner magnetosphere where Custer significantly improved knowledge. After estimating the outflow flux and destinations, complicated ion dynamics in the inner magnetosphere was classified and summarized, through which more than half the O+ is finally lost to space. Together with direct escapes, total O+ escape is high enough to influence the evolution of the biosphere.
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Extraction of the solar wind kinetic energy (∆K) by mass loading of escaping O+ is modelled in the exterior cusp and plasma mantle of the Earth. We found ∆K proportional to mass flux of escaping ions and square of solar wind velocity, but independent to the other parameters. The amount is sufficient to power the cusp field-aligned currents, further enhancing ion escape through Joule heating of the ionospheric ions, completing positive feedback to enhance escape with geomagnetic activities.
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The Earth's atmosphere is constantly losing ions and in particular oxygen ions. This phenomenon is important to understand the atmospheric evolution on a large timescale. In this study, the O+ outflow is estimated during six extreme geomagnetic storms using the European Cluster mission data. These estimations are compared with average magnetospheric conditions and show that during those six extreme storms, the O+ outflow is approximately 2 orders of magnitude higher.
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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.
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In this study, we have used Cluster satellite data to quantify the ionospheric oxygen ion (O+) escape into the solar wind and its dependence on geomagnetic activity. During times of high activity, the escape may be 2 orders of magnitude higher than under quiet conditions, strongly suggesting that the escape rate was much higher when the Sun was young. The results are important for future studies regarding atmospheric loss over geological timescales.
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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
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Daedalus aims to measure the largely unexplored area between Eart's atmosphere and space, the Earth's
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Masatoshi Yamauchi
Ann. Geophys., 37, 1197–1222, https://doi.org/10.5194/angeo-37-1197-2019, https://doi.org/10.5194/angeo-37-1197-2019, 2019
Short summary
Short summary
Terrestrial ion transport and total escape are synthesized, with stress on the high-latitude polar region and the inner magnetosphere where Custer significantly improved knowledge. After estimating the outflow flux and destinations, complicated ion dynamics in the inner magnetosphere was classified and summarized, through which more than half the O+ is finally lost to space. Together with direct escapes, total O+ escape is high enough to influence the evolution of the biosphere.
Xinhua Wei, Chunlin Cai, Henri Rème, Iannis Dandouras, and George Parks
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2018-124, https://doi.org/10.5194/angeo-2018-124, 2018
Revised manuscript not accepted
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Observations of flapping current sheet in the magnetotail are presented to reveal their intrinsic excitation mechanism induced by alternating north-south asymmetric ion populations in the sheet center. The results suggest that nonadiabatic ions play a substantial role to determine current sheet dynamics, both its bulk mechanical instability and current profiles.
Masatoshi Yamauchi and Rikard Slapak
Ann. Geophys., 36, 1–12, https://doi.org/10.5194/angeo-36-1-2018, https://doi.org/10.5194/angeo-36-1-2018, 2018
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Extraction of the solar wind kinetic energy (∆K) by mass loading of escaping O+ is modelled in the exterior cusp and plasma mantle of the Earth. We found ∆K proportional to mass flux of escaping ions and square of solar wind velocity, but independent to the other parameters. The amount is sufficient to power the cusp field-aligned currents, further enhancing ion escape through Joule heating of the ionospheric ions, completing positive feedback to enhance escape with geomagnetic activities.
Audrey Schillings, Hans Nilsson, Rikard Slapak, Masatoshi Yamauchi, and Lars-Göran Westerberg
Ann. Geophys., 35, 1341–1352, https://doi.org/10.5194/angeo-35-1341-2017, https://doi.org/10.5194/angeo-35-1341-2017, 2017
Short summary
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The Earth's atmosphere is constantly losing ions and in particular oxygen ions. This phenomenon is important to understand the atmospheric evolution on a large timescale. In this study, the O+ outflow is estimated during six extreme geomagnetic storms using the European Cluster mission data. These estimations are compared with average magnetospheric conditions and show that during those six extreme storms, the O+ outflow is approximately 2 orders of magnitude higher.
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
Short summary
Short summary
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.
Rikard Slapak, Audrey Schillings, Hans Nilsson, Masatoshi Yamauchi, Lars-Göran Westerberg, and Iannis Dandouras
Ann. Geophys., 35, 721–731, https://doi.org/10.5194/angeo-35-721-2017, https://doi.org/10.5194/angeo-35-721-2017, 2017
Short summary
Short summary
In this study, we have used Cluster satellite data to quantify the ionospheric oxygen ion (O+) escape into the solar wind and its dependence on geomagnetic activity. During times of high activity, the escape may be 2 orders of magnitude higher than under quiet conditions, strongly suggesting that the escape rate was much higher when the Sun was young. The results are important for future studies regarding atmospheric loss over geological timescales.
Dhvanit Mehta, Andrew J. Gerrard, Yusuke Ebihara, Allan T. Weatherwax, and Louis J. Lanzerotti
Atmos. Chem. Phys., 17, 911–919, https://doi.org/10.5194/acp-17-911-2017, https://doi.org/10.5194/acp-17-911-2017, 2017
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This paper presents an investigation into the sources of atmospheric gravity waves observed at 90 km above Amundsen-Scott South Pole Station, Antarctica. By combining gravity wave characteristics obtained from imager data and a numerical model for 3-D wave propagation through the atmosphere, we find that the development of baroclinic instabilities via displacement of the polar vortex is a significant and unique source of vertically propagating, short-period (< 1 h) gravity waves in the region.
R. Kataoka, Y. Fukuda, H. A. Uchida, H. Yamada, Y. Miyoshi, Y. Ebihara, H. Dahlgren, and D. Hampton
Ann. Geophys., 34, 41–44, https://doi.org/10.5194/angeo-34-41-2016, https://doi.org/10.5194/angeo-34-41-2016, 2016
Short summary
Short summary
Stereoscopy of aurora was performed at the record fast sampling rate of 100 fps to measure the emission altitude of rapidly varying fine-scale structures. The new method unveiled that very different types of aurora appear in the same direction at different altitudes.
N. Y. Ganushkina, M. W. Liemohn, S. Dubyagin, I. A. Daglis, I. Dandouras, D. L. De Zeeuw, Y. Ebihara, R. Ilie, R. Katus, M. Kubyshkina, S. E. Milan, S. Ohtani, N. Ostgaard, J. P. Reistad, P. Tenfjord, F. Toffoletto, S. Zaharia, and O. Amariutei
Ann. Geophys., 33, 1369–1402, https://doi.org/10.5194/angeo-33-1369-2015, https://doi.org/10.5194/angeo-33-1369-2015, 2015
Short summary
Short summary
A number of current systems exist in the Earth's magnetosphere. It is very difficult to identify local measurements as belonging to a specific current system. Therefore, there are different definitions of supposedly the same current, leading to unnecessary controversy. This study presents a robust collection of these definitions of current systems in geospace, particularly in the near-Earth nightside magnetosphere, as viewed from a variety of observational and computational analysis techniques.
E. Lee, G. K. Parks, S. Y. Fu, M. Fillingim, Y. B. Cui, J. Hong, I. Dandouras, and H. Rème
Ann. Geophys., 33, 1263–1269, https://doi.org/10.5194/angeo-33-1263-2015, https://doi.org/10.5194/angeo-33-1263-2015, 2015
G. K. Parks, E. Lee, S. Y. Fu, M. Fillingim, I. Dandouras, Y. B. Cui, J. Hong, and H. Rème
Ann. Geophys., 33, 333–344, https://doi.org/10.5194/angeo-33-333-2015, https://doi.org/10.5194/angeo-33-333-2015, 2015
Short summary
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Ions from Earth's ionosphere continually escape into space. This article examines ions escaping the auroral oval, a region in the polar region of Earth where auroras occur. Previous works have shown that ionospheric ions escape during active auroras, and more as the intensity of the aurora increases. In contrast, we have examined times of no auroras and find that ions are still escaping the auroral ionosphere. These escaping ions are an important source of auroral ions in the magnetosphere.
A. Varsani, C. J. Owen, A. N. Fazakerley, C. Forsyth, A. P. Walsh, M. André, I. Dandouras, and C. M. Carr
Ann. Geophys., 32, 1093–1117, https://doi.org/10.5194/angeo-32-1093-2014, https://doi.org/10.5194/angeo-32-1093-2014, 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
A. Blagau, I. Dandouras, A. Barthe, S. Brunato, G. Facskó, and V. Constantinescu
Geosci. Instrum. Method. Data Syst., 3, 49–58, https://doi.org/10.5194/gi-3-49-2014, https://doi.org/10.5194/gi-3-49-2014, 2014
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
M. Yamauchi, I. Dandouras, H. Rème, R. Lundin, and L. M. Kistler
Ann. Geophys., 31, 1569–1578, https://doi.org/10.5194/angeo-31-1569-2013, https://doi.org/10.5194/angeo-31-1569-2013, 2013
I. Dandouras
Ann. Geophys., 31, 1143–1153, https://doi.org/10.5194/angeo-31-1143-2013, https://doi.org/10.5194/angeo-31-1143-2013, 2013
C. P. Escoubet, J. Berchem, K. J. Trattner, F. Pitout, R. Richard, M. G. G. T. Taylor, J. Soucek, B. Grison, H. Laakso, A. Masson, M. Dunlop, I. Dandouras, H. Reme, A. Fazakerley, and P. Daly
Ann. Geophys., 31, 713–723, https://doi.org/10.5194/angeo-31-713-2013, https://doi.org/10.5194/angeo-31-713-2013, 2013
