Articles | Volume 36, issue 6
https://doi.org/10.5194/angeo-36-1577-2018
© 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-36-1577-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
29 Nov 2018
Regular paper |
| 29 Nov 2018
| 29 Nov 2018
The asymmetric geospace as displayed during the geomagnetic storm on 17 August 2001
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Jone P. Reistad
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Paul Tenfjord
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Karl M. Laundal
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Theresa Rexer
Department of Physics and Technology, University of Tromsø, 9037 Tromsø, Norway
Stein E. Haaland
Department of Planets and Comets, Max-Planck Institute for Solar System Research, Göttingen, Germany
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Kristian Snekvik
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Michael Hesse
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Stephen E. Milan
Department of Physics and Astronomy, University of Leicester, Leicester, UK
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
Anders Ohma
Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
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Related subject area
Subject: Magnetosphere & space plasma physics | Keywords: Solar wind–magnetosphere interactions
Velocity of magnetic holes in the solar wind from Cluster multipoint measurements
Storm time polar cap expansion: interplanetary magnetic field clock angle dependence
Solar wind magnetic holes can cross the bow shock and enter the magnetosheath
Comment on
From the Sun to Earth: effects of the 25 August 2018 geomagnetic storm
GUMICS-4 analysis of interplanetary coronal mass ejection impact on Earth during low and typical Mach number solar winds
Local time extent of magnetopause reconnection using space–ground coordination
Transfer entropy and cumulant-based cost as measures of nonlinear causal relationships in space plasmas: applications to Dst
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.
Beket Tulegenov, Joachim Raeder, William D. Cramer, Banafsheh Ferdousi, Timothy J. Fuller-Rowell, Naomi Maruyama, and Robert J. Strangeway
Ann. Geophys., 41, 39–54, https://doi.org/10.5194/angeo-41-39-2023, https://doi.org/10.5194/angeo-41-39-2023, 2023
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We study how the polar regions of the Earth connect to space along magnetic field lines. While the Earth's magnetic field is mostly the shape of a dipole, at high latitudes the field lines tend to be open and connect to interplanetary space. This area of open field line is called the polar cap, and it is highly dynamic. Through data analysis and computer simulations, we find that the shape of the polar cap is closely controlled by the magnetic field embedded in 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.
Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric fieldby Troshichev et al. (2011)
Peter Stauning
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2020-52, https://doi.org/10.5194/angeo-2020-52, 2020
Preprint withdrawn
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In Troshichev et al. (2006) an error was made in the calculations of Polar Cap (PC) index scaling parameters. For the publication commented here, Troshichev et al. (2011), the authors state having used scaling parameters of the invalid PC index version but have actually substituted parameters from another version instead. The mingling of PC index versions has resulted in erroneous illustrations in Figs. 1, 2, 3, 6, 7, and 8 and the issuing of non-substantiated statements.
Mirko Piersanti, Paola De Michelis, Dario Del Moro, Roberta Tozzi, Michael Pezzopane, Giuseppe Consolini, Maria Federica Marcucci, Monica Laurenza, Simone Di Matteo, Alessio Pignalberi, Virgilio Quattrociocchi, and Piero Diego
Ann. Geophys., 38, 703–724, https://doi.org/10.5194/angeo-38-703-2020, https://doi.org/10.5194/angeo-38-703-2020, 2020
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This paper presents a comprehensive analysis of the solar event that occurred on 25 August 2018. This kind of comprehensive analysis plays a key role in better understanding the complexity of the processes occurring in the Sun–Earth system determining the geoeffectiveness of manifestations of solar activity. The analysis presented here shows for the first time a direct link between characteristics of solar perturbation, the magnetosphere–ionosphere system response and space weather effects.
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.
Ying Zou, Brian M. Walsh, Yukitoshi Nishimura, Vassilis Angelopoulos, J. Michael Ruohoniemi, Kathryn A. McWilliams, and Nozomu Nishitani
Ann. Geophys., 37, 215–234, https://doi.org/10.5194/angeo-37-215-2019, https://doi.org/10.5194/angeo-37-215-2019, 2019
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Magnetopause reconnection is a process whereby the Sun explosively transfers energy to the Earth. Whether the process is spatially patchy or spatially continuous and extended has been under long debate. We use space–ground coordination to overcome the limitations of previous studies and reliably interpret spatial extent. Our result strongly indicates that both patchy and extended reconnection is possible and, interestingly, that extended reconnection grows from a localized patch via spreading.
Jay R. Johnson, Simon Wing, and Enrico Camporeale
Ann. Geophys., 36, 945–952, https://doi.org/10.5194/angeo-36-945-2018, https://doi.org/10.5194/angeo-36-945-2018, 2018
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The magnetospheric response to the solar wind is nonlinear. Information theoretical tools are able to characterize the nonlinearities in the system. We show that nonlinear significance of Dst peaks at lags of 3–12 hours which can be attributed to VBs, which also exhibits similar behavior. However, the nonlinear significance that peaks at lags of 25, 50, and 90 hours can be attributed to internal dynamics, which may be related to the relaxation of the ring current.
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Short summary
In this paper we take advantage of having two auroral imaging missions giving simultaneous data of both the southern and northern aurora. Combined with all available in situ measurements from space and global ground-based networks, we explore the asymmetric behavior of geospace. We find large auroral asymmetries and different reconnection geometry in the two hemispheres. During substorm expansion phase asymmetries are reduced.
In this paper we take advantage of having two auroral imaging missions giving simultaneous data...
