Articles | Volume 32, issue 9
https://doi.org/10.5194/angeo-32-1093-2014
© 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-32-1093-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Regular paper
| 
08 Sep 2014
Regular paper |
| 08 Sep 2014
Cluster observations of the substructure of a flux transfer event: analysis of high-time-resolution particle data
A. Varsani
UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK
C. J. Owen
UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK
A. N. Fazakerley
UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK
C. Forsyth
UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK
A. P. Walsh
UCL Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, RH5 6NT, UK
now at: Science and Robotic Exploration Directorate, European Space Agency, ESAC, Villanueva de la Cañada, Madrid, Spain
Swedish Institute of Space Physics, Uppsala, Sweden
I. Dandouras
IRAP, CNRS/Université de Toulouse, Toulouse, France
C. M. Carr
Blackett Laboratory, Imperial College, London, UK
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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.
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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
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
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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.
Shuai Zhang, Anmin Tian, Quanqi Shi, Hanlin Li, Alexander W. Degeling, I. Jonathan Rae, Colin Forsyth, Mengmeng Wang, Xiaochen Shen, Weijie Sun, Shichen Bai, Ruilong Guo, Huizi Wang, Andrew Fazakerley, Suiyan Fu, and Zuyin Pu
Ann. Geophys., 36, 1335–1346, https://doi.org/10.5194/angeo-36-1335-2018, https://doi.org/10.5194/angeo-36-1335-2018, 2018
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The features of ULF waves are statistically studied on the magnetotail stretched magnetic field lines (8 RE < R < 32 RE) by using 8 years of THEMIS data. The occurrence rates of ULF waves are higher in the post-midnight region than pre-midnight region. The frequency decreases with increasing radial distance of 8–16 RE and could be explained by much more standing waves in this region than in the region of 16–32 RE. The wave frequency is higher after the substorm onset than before it.
Allan R. Macneil, Christopher J. Owen, and Robert T. Wicks
Ann. Geophys., 35, 1275–1291, https://doi.org/10.5194/angeo-35-1275-2017, https://doi.org/10.5194/angeo-35-1275-2017, 2017
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We aim to understand the link between the Sun's atmosphere, the corona, and the constant stream of plasma which escapes it, the solar wind. To do so we test how similar energetic electrons in the solar wind are to their earlier state in the corona, using oxygen ionisation states as a proxy. We find only a very weak link which varies with the type of solar wind stream and the 11-year solar cycle. We find minor evidence to suggest that this is due to solar wind processing during its outward flow.
Simon Thomas, Mathew Owens, Mike Lockwood, and Chris Owen
Ann. Geophys., 35, 825–838, https://doi.org/10.5194/angeo-35-825-2017, https://doi.org/10.5194/angeo-35-825-2017, 2017
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Galactic cosmic rays are high-energy particles from outside of the solar system. The products of their interaction with the atmosphere are counted by a network of neutron monitors. The number of cosmic rays reaching Earth is affected by the magnetic field embedded in the solar wind. The result is a number of regular variations in the neutron monitor data, including a diurnal variation. We have found that this variation is influenced by 1–2 h by the polarity of the Sun's magnetic field.
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
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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.
Ingo Richter, Hans-Ulrich Auster, Gerhard Berghofer, Chris Carr, Emanuele Cupido, Karl-Heinz Fornaçon, Charlotte Goetz, Philip Heinisch, Christoph Koenders, Bernd Stoll, Bruce T. Tsurutani, Claire Vallat, Martin Volwerk, and Karl-Heinz Glassmeier
Ann. Geophys., 34, 609–622, https://doi.org/10.5194/angeo-34-609-2016, https://doi.org/10.5194/angeo-34-609-2016, 2016
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We have analysed the magnetic field measurements performed on the ROSETTA orbiter and the lander PHILAE during PHILAE's descent to comet 67P/Churyumov-Gerasimenko on 12 November 2014. We observed a new type of low-frequency wave with amplitudes of ~ 3 nT, frequencies of 20–50 mHz, wavelengths of ~ 300 km, and propagation velocities of ~ 6 km s−1. The waves are generated in a ~ 100 km region around the comet a show a highly correlated behaviour, which could only be determined by two-point observations.
M. Volwerk, I. Richter, B. Tsurutani, C. Götz, K. Altwegg, T. Broiles, J. Burch, C. Carr, E. Cupido, M. Delva, M. Dósa, N. J. T. Edberg, A. Eriksson, P. Henri, C. Koenders, J.-P. Lebreton, K. E. Mandt, H. Nilsson, A. Opitz, M. Rubin, K. Schwingenschuh, G. Stenberg Wieser, K. Szegö, C. Vallat, X. Vallieres, and K.-H. Glassmeier
Ann. Geophys., 34, 1–15, https://doi.org/10.5194/angeo-34-1-2016, https://doi.org/10.5194/angeo-34-1-2016, 2016
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The solar wind magnetic field drapes around the active nucleus of comet 67P/CG, creating a magnetosphere. The solar wind density increases and with that the pressure, which compresses the magnetosphere, increasing the magnetic field strength near Rosetta. The higher solar wind density also creates more ionization through collisions with the gas from the comet. The new ions are picked-up by the magnetic field and generate mirror-mode waves, creating low-field high-density "bottles" near 67P/CG.
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
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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.
Z. H. Yao, J. Liu, C. J. Owen, C. Forsyth, I. J. Rae, Z. Y. Pu, H. S. Fu, X.-Z. Zhou, Q. Q. Shi, A. M. Du, R. L. Guo, and X. N. Chu
Ann. Geophys., 33, 1301–1309, https://doi.org/10.5194/angeo-33-1301-2015, https://doi.org/10.5194/angeo-33-1301-2015, 2015
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We use THEMIS large data set of dipolarization front events to build a 2-D pressure distribution in XZ plane, and thus derive the current system around the dipolarization front. Our results show that a banana current loop is formed around the dipolarization front. This current is also suggested to be the reason for the magnetic dip observed ahead of the dipolarization front. In addition, the current density is too small to contribute a substorm current wedge.
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
I. Richter, C. Koenders, H.-U. Auster, D. Frühauff, C. Götz, P. Heinisch, C. Perschke, U. Motschmann, B. Stoll, K. Altwegg, J. Burch, C. Carr, E. Cupido, A. Eriksson, P. Henri, R. Goldstein, J.-P. Lebreton, P. Mokashi, Z. Nemeth, H. Nilsson, M. Rubin, K. Szegö, B. T. Tsurutani, C. Vallat, M. Volwerk, and K.-H. Glassmeier
Ann. Geophys., 33, 1031–1036, https://doi.org/10.5194/angeo-33-1031-2015, https://doi.org/10.5194/angeo-33-1031-2015, 2015
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We present a first report on magnetic field measurements made in the coma of comet 67P/C-G in its low-activity state. The plasma environment is dominated by quasi-coherent, large-amplitude, compressional magnetic field oscillations around 40mHz, differing from the observations at strongly active comets where waves at the cometary ion gyro-frequencies are the main feature. We propose a cross-field current instability associated with the newborn cometary ions as a possible source mechanism.
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
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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.
Y. V. Khotyaintsev, P.-A. Lindqvist, C. M. Cully, A. I. Eriksson, and M. André
Geosci. Instrum. Method. Data Syst., 3, 143–151, https://doi.org/10.5194/gi-3-143-2014, https://doi.org/10.5194/gi-3-143-2014, 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
L. N. S. Alconcel, P. Fox, P. Brown, T. M. Oddy, E. L. Lucek, and C. M. Carr
Geosci. Instrum. Method. Data Syst., 3, 95–109, https://doi.org/10.5194/gi-3-95-2014, https://doi.org/10.5194/gi-3-95-2014, 2014
A. P. Walsh, S. Haaland, C. Forsyth, A. M. Keesee, J. Kissinger, K. Li, A. Runov, J. Soucek, B. M. Walsh, S. Wing, and M. G. G. T. Taylor
Ann. Geophys., 32, 705–737, https://doi.org/10.5194/angeo-32-705-2014, https://doi.org/10.5194/angeo-32-705-2014, 2014
N. Doss, A. N. Fazakerley, B. Mihaljčić, A. D. Lahiff, R. J. Wilson, D. Kataria, I. Rozum, G. Watson, and Y. Bogdanova
Geosci. Instrum. Method. Data Syst., 3, 59–70, https://doi.org/10.5194/gi-3-59-2014, https://doi.org/10.5194/gi-3-59-2014, 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
M. Yamauchi, Y. Ebihara, H. Nilsson, and I. Dandouras
Ann. Geophys., 32, 83–90, https://doi.org/10.5194/angeo-32-83-2014, https://doi.org/10.5194/angeo-32-83-2014, 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. A. Pudney, C. M. Carr, S. J. Schwartz, and S. I. Howarth
Geosci. Instrum. Method. Data Syst., 2, 249–255, https://doi.org/10.5194/gi-2-249-2013, https://doi.org/10.5194/gi-2-249-2013, 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
M. Volwerk, N. André, C. S. Arridge, C. M. Jackman, X. Jia, S. E. Milan, A. Radioti, M. F. Vogt, A. P. Walsh, R. Nakamura, A. Masters, and C. Forsyth
Ann. Geophys., 31, 817–833, https://doi.org/10.5194/angeo-31-817-2013, https://doi.org/10.5194/angeo-31-817-2013, 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
