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Turc L, Roberts OW, Verscharen D, Dimmock AP, Kajdič P, Palmroth M, Pfau-Kempf Y, Johlander A, Dubart M, Kilpua EKJ, Soucek J, Takahashi K, Takahashi N, Battarbee M, Ganse U. Transmission of foreshock waves through Earth's bow shock. Nat Phys 2022; 19:78-86. [PMID: 36687291 PMCID: PMC9845118 DOI: 10.1038/s41567-022-01837-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
The Earth's magnetosphere and its bow shock, which is formed by the interaction of the supersonic solar wind with the terrestrial magnetic field, constitute a rich natural laboratory enabling in situ investigations of universal plasma processes. Under suitable interplanetary magnetic field conditions, a foreshock with intense wave activity forms upstream of the bow shock. So-called 30 s waves, named after their typical period at Earth, are the dominant wave mode in the foreshock and play an important role in modulating the shape of the shock front and affect particle reflection at the shock. These waves are also observed inside the magnetosphere and down to the Earth's surface, but how they are transmitted through the bow shock remains unknown. By combining state-of-the-art global numerical simulations and spacecraft observations, we demonstrate that the interaction of foreshock waves with the shock generates earthward-propagating, fast-mode waves, which reach the magnetosphere. These findings give crucial insight into the interaction of waves with collisionless shocks in general and their impact on the downstream medium.
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Affiliation(s)
- L. Turc
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - O. W. Roberts
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - D. Verscharen
- Mullard Space Science Laboratory, University College London, Dorking, UK
| | | | - P. Kajdič
- Departamento de Ciencias Espaciales, Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - M. Palmroth
- Department of Physics, University of Helsinki, Helsinki, Finland
- Finnish Meteorological Institute, Helsinki, Finland
| | - Y. Pfau-Kempf
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - A. Johlander
- Department of Physics, University of Helsinki, Helsinki, Finland
- Swedish Institute of Space Physics, Uppsala, Sweden
| | - M. Dubart
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - E. K. J. Kilpua
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - J. Soucek
- Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - K. Takahashi
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - N. Takahashi
- Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Tokyo, Japan
- Radio Research Institute, National Institute of Information and Communication Technology, Tokyo, Japan
| | - M. Battarbee
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - U. Ganse
- Department of Physics, University of Helsinki, Helsinki, Finland
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Möstl C, Amerstorfer T, Palmerio E, Isavnin A, Farrugia CJ, Lowder C, Winslow RM, Donnerer JM, Kilpua EKJ, Boakes PD. Forward Modeling of Coronal Mass Ejection Flux Ropes in the Inner Heliosphere with 3DCORE. Space Weather 2018; 16:216-229. [PMID: 29780287 PMCID: PMC5947730 DOI: 10.1002/2017sw001735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/20/2017] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Forecasting the geomagnetic effects of solar storms, known as coronal mass ejections (CMEs), is currently severely limited by our inability to predict the magnetic field configuration in the CME magnetic core and by observational effects of a single spacecraft trajectory through its 3-D structure. CME magnetic flux ropes can lead to continuous forcing of the energy input to the Earth's magnetosphere by strong and steady southward-pointing magnetic fields. Here we demonstrate in a proof-of-concept way a new approach to predict the southward field B z in a CME flux rope. It combines a novel semiempirical model of CME flux rope magnetic fields (Three-Dimensional Coronal ROpe Ejection) with solar observations and in situ magnetic field data from along the Sun-Earth line. These are provided here by the MESSENGER spacecraft for a CME event on 9-13 July 2013. Three-Dimensional Coronal ROpe Ejection is the first such model that contains the interplanetary propagation and evolution of a 3-D flux rope magnetic field, the observation by a synthetic spacecraft, and the prediction of an index of geomagnetic activity. A counterclockwise rotation of the left-handed erupting CME flux rope in the corona of 30° and a deflection angle of 20° is evident from comparison of solar and coronal observations. The calculated Dst matches reasonably the observed Dst minimum and its time evolution, but the results are highly sensitive to the CME axis orientation. We discuss assumptions and limitations of the method prototype and its potential for real time space weather forecasting and heliospheric data interpretation.
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Affiliation(s)
- C. Möstl
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - T. Amerstorfer
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - E. Palmerio
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - A. Isavnin
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - C. J. Farrugia
- Institute for the Study of Earth, Oceans, and SpaceUniversity of New HampshireDurhamNHUSA
| | - C. Lowder
- Department of Mathematical SciencesDurham UniversityDurhamUK
- Southwest Research InstituteBoulderCOUSA
| | - R. M. Winslow
- Institute for the Study of Earth, Oceans, and SpaceUniversity of New HampshireDurhamNHUSA
| | - J. M. Donnerer
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | | | - P. D. Boakes
- Space Research InstituteAustrian Academy of SciencesGrazAustria
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Möstl C, Isavnin A, Boakes PD, Kilpua EKJ, Davies JA, Harrison RA, Barnes D, Krupar V, Eastwood JP, Good SW, Forsyth RJ, Bothmer V, Reiss MA, Amerstorfer T, Winslow RM, Anderson BJ, Philpott LC, Rodriguez L, Rouillard AP, Gallagher P, Nieves-Chinchilla T, Zhang TL. Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the Heliophysics System Observatory. Space Weather 2017; 15:955-970. [PMID: 28983209 PMCID: PMC5601179 DOI: 10.1002/2017sw001614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/18/2017] [Accepted: 06/30/2017] [Indexed: 06/07/2023]
Abstract
We present an advance toward accurately predicting the arrivals of coronal mass ejections (CMEs) at the terrestrial planets, including Earth. For the first time, we are able to assess a CME prediction model using data over two thirds of a solar cycle of observations with the Heliophysics System Observatory. We validate modeling results of 1337 CMEs observed with the Solar Terrestrial Relations Observatory (STEREO) heliospheric imagers (HI) (science data) from 8 years of observations by five in situ observing spacecraft. We use the self-similar expansion model for CME fronts assuming 60° longitudinal width, constant speed, and constant propagation direction. With these assumptions we find that 23%-35% of all CMEs that were predicted to hit a certain spacecraft lead to clear in situ signatures, so that for one correct prediction, two to three false alarms would have been issued. In addition, we find that the prediction accuracy does not degrade with the HI longitudinal separation from Earth. Predicted arrival times are on average within 2.6 ± 16.6 h difference of the in situ arrival time, similar to analytical and numerical modeling, and a true skill statistic of 0.21. We also discuss various factors that may improve the accuracy of space weather forecasting using wide-angle heliospheric imager observations. These results form a first-order approximated baseline of the prediction accuracy that is possible with HI and other methods used for data by an operational space weather mission at the Sun-Earth L5 point.
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Affiliation(s)
- C Möstl
- Space Research Institute Austrian Academy of Sciences Graz Austria
- IGAM-Kanzelhöhe Observatory, Institute of Physics University of Graz Graz Austria
| | - A Isavnin
- Department of Physics University of Helsinki Helsinki Finland
| | - P D Boakes
- Space Research Institute Austrian Academy of Sciences Graz Austria
- IGAM-Kanzelhöhe Observatory, Institute of Physics University of Graz Graz Austria
| | - E K J Kilpua
- Department of Physics University of Helsinki Helsinki Finland
| | - J A Davies
- RAL Space Rutherford Appleton Laboratory Harwell UK
| | - R A Harrison
- RAL Space Rutherford Appleton Laboratory Harwell UK
| | - D Barnes
- RAL Space Rutherford Appleton Laboratory Harwell UK
- University College London London UK
| | - V Krupar
- Institute of Atmospheric Physics CAS Prague Czech Republic
| | - J P Eastwood
- Blackett Laboratory Imperial College London London UK
| | - S W Good
- Blackett Laboratory Imperial College London London UK
| | - R J Forsyth
- Blackett Laboratory Imperial College London London UK
| | - V Bothmer
- Institute for Astrophysics University of Göttingen Göttingen Germany
| | - M A Reiss
- IGAM-Kanzelhöhe Observatory, Institute of Physics University of Graz Graz Austria
| | - T Amerstorfer
- Space Research Institute Austrian Academy of Sciences Graz Austria
| | - R M Winslow
- Institute for the Study of Earth, Oceans, and Space University of New Hampshire Durham New Hampshire USA
| | - B J Anderson
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
| | - L C Philpott
- Department of Earth, Ocean and Atmospheric Sciences University of British Columbia Vancouver British Columbia Canada
| | - L Rodriguez
- Solar Terrestrial Center of Excellence-SIDC Royal Observatory of Belgium Brussels Belgium
| | - A P Rouillard
- Institut de Recherche en Astrophysique et Planétologie Université de Toulouse (UPS) Toulouse France
- Centre National de la Recherche Scientifique Toulouse France
| | - P Gallagher
- School of Physics Trinity College Dublin Ireland
| | | | - T L Zhang
- Space Research Institute Austrian Academy of Sciences Graz Austria
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James AW, Green LM, Palmerio E, Valori G, Reid HAS, Baker D, Brooks DH, van Driel-Gesztelyi L, Kilpua EKJ. On-Disc Observations of Flux Rope Formation Prior to Its Eruption. Sol Phys 2017; 292:71. [PMID: 32055079 PMCID: PMC6991970 DOI: 10.1007/s11207-017-1093-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/09/2017] [Indexed: 06/09/2023]
Abstract
Coronal mass ejections (CMEs) are one of the primary manifestations of solar activity and can drive severe space weather effects. Therefore, it is vital to work towards being able to predict their occurrence. However, many aspects of CME formation and eruption remain unclear, including whether magnetic flux ropes are present before the onset of eruption and the key mechanisms that cause CMEs to occur. In this work, the pre-eruptive coronal configuration of an active region that produced an interplanetary CME with a clear magnetic flux rope structure at 1 AU is studied. A forward-S sigmoid appears in extreme-ultraviolet (EUV) data two hours before the onset of the eruption (SOL2012-06-14), which is interpreted as a signature of a right-handed flux rope that formed prior to the eruption. Flare ribbons and EUV dimmings are used to infer the locations of the flux rope footpoints. These locations, together with observations of the global magnetic flux distribution, indicate that an interaction between newly emerged magnetic flux and pre-existing sunspot field in the days prior to the eruption may have enabled the coronal flux rope to form via tether-cutting-like reconnection. Composition analysis suggests that the flux rope had a coronal plasma composition, supporting our interpretation that the flux rope formed via magnetic reconnection in the corona. Once formed, the flux rope remained stable for two hours before erupting as a CME. ELECTRONIC SUPPLEMENTARY MATERIAL The online version of this article (doi:10.1007/s11207-017-1093-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A. W. James
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT UK
| | - L. M. Green
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT UK
| | - E. Palmerio
- Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
| | - G. Valori
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT UK
| | - H. A. S. Reid
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - D. Baker
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT UK
| | - D. H. Brooks
- College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 USA
| | - L. van Driel-Gesztelyi
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT UK
- Observatoire de Paris, LESIA, FRE 2461 (CNRS), 92195 Meudon Principal Cedex, France
- Konkoly Observatory of the Hungarian Academy of Sciences, Budapest, Hungary
| | - E. K. J. Kilpua
- Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland
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Lugaz N, Farrugia CJ, Winslow RM, Al-Haddad N, Kilpua EKJ, Riley P. Factors Affecting the Geo-effectiveness of Shocks and Sheaths at 1 AU. J Geophys Res Space Phys 2016; 121:10861-10879. [PMID: 29629250 PMCID: PMC5882492 DOI: 10.1002/2016ja023100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We identify all fast-mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes and geo-effects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geo-effective sheaths compress pre-existing southward Bz . Most of the remaining sheaths appear to have planar structures with southward magnetic fields, including some with planar structures consistent with field line draping ahead of the magnetic ejecta. A typical (median) geo-effective shock-sheath structure drives a geomagnetic storm with peak Dst of -88 nT, pushes the subsolar magnetopause location to 6.3 RE, i.e. below geosynchronous orbit and is associated with substorms with a peak AL-index of -1350 nT. There are some important differences between sheaths associated with CME-CME interaction (stronger storms) and those associated with isolated CMEs (stronger compression of the magnetosphere). We detail six case studies of different types of geo-effective shock-sheaths, as well as two events for which there was no geomagnetic storm but other magnetospheric effects. Finally, we discuss our results in terms of space weather forecasting, and potential effects on Earth's radiation belts.
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Affiliation(s)
- N. Lugaz
- Space Science Center, University of New Hampshire, Durham, NH, USA
- Department of Physics, University of New Hampshire, Durham, NH, USA
| | - C. J. Farrugia
- Space Science Center, University of New Hampshire, Durham, NH, USA
- Department of Physics, University of New Hampshire, Durham, NH, USA
| | - R. M. Winslow
- Space Science Center, University of New Hampshire, Durham, NH, USA
| | - N. Al-Haddad
- Department of Physics, University of New Hampshire, Durham, NH, USA
- Institute for Astrophysics and Computational Sciences, Catholic University of America, Washington, DC, USA
| | - E. K. J. Kilpua
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - P. Riley
- Predictive Sciences Inc., San Diego, CA, USA
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6
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Hietala H, Agueda N, Andréeová K, Vainio R, Nylund S, Kilpua EKJ, Koskinen HEJ. In situ observations of particle acceleration in shock-shock interaction. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016669] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- H. Hietala
- Department of Physics; University of Helsinki; Helsinki Finland
| | - N. Agueda
- Space Science Laboratory; University of California; Berkeley California USA
- Departament d'Astronomia i Meteorologia, Institut de Ciències del Cosmos; Universitat de Barcelona; Barcelona Spain
| | - K. Andréeová
- Department of Physics; University of Helsinki; Helsinki Finland
| | - R. Vainio
- Department of Physics; University of Helsinki; Helsinki Finland
| | - S. Nylund
- Applied Physics Laboratory; Johns Hopkins University; Laurel Maryland USA
| | - E. K. J. Kilpua
- Department of Physics; University of Helsinki; Helsinki Finland
| | - H. E. J. Koskinen
- Department of Physics; University of Helsinki; Helsinki Finland
- Finnish Meteorological Institute; Helsinki Finland
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