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Abstract
An accurate understanding of dissimilarities in geomagnetic variability between quiet and disturbed periods has the potential to vastly improve space weather diagnosis. In this work, we exploit some recently developed methods of dynamical system theory to provide new insights and conceptual ideas in space weather science. In particular, we study the co-variation and recurrence statistics of two geomagnetic indices, SYM-H and AL, that measure the intensity of the globally symmetric component of the equatorial electrojet and that of the westward auroral electrojet, respectively. We find that the number of active degrees of freedom, required to describe the phase space dynamics of both indices, depends on the geomagnetic activity level. When the magnetospheric substorm activity, as monitored by the AL index, increases, the active number of degrees of freedom increases at high latitudes above the dimension obtained through classical time delay embedding methods. Conversely, a reduced number of degrees of freedom is observed during geomagnetic storms at low latitude by analysing the SYM-H index. By investigating time-dependent relations between both indices we find that a significant amount of information is shared between high and low latitude current systems originating from coupling mechanisms within the magnetosphere–ionosphere system as the result of a complex interplay between processes and phenomena of internal origin activated by the triggering of external source processes. Our observations support the idea that the near-Earth electromagnetic environment is a complex system far from an equilibrium.
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The August 2018 Geomagnetic Storm Observed by the High-Energy Particle Detector on Board the CSES-01 Satellite. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11125680] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
On 25 August 2018, a G3-class geomagnetic storm reached the Earth’s magnetosphere, causing a transient rearrangement of the charged particle environment around the planet, which was detected by the High-Energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01). We found that the count rates of electrons in the MeV range were characterized by a depletion during the storm’s main phase and a clear enhancement during the recovery caused by large substorm activity, with the key role played by auroral processes mapped into the outer belt. A post-storm rate increase was localized at L-shells immediately above ∼3 and mostly driven by non-adiabatic local acceleration caused by possible resonant interaction with low-frequency magnetospheric waves.
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Orr L, Chapman SC, Gjerloev JW, Guo W. Network community structure of substorms using SuperMAG magnetometers. Nat Commun 2021; 12:1842. [PMID: 33758181 PMCID: PMC7988152 DOI: 10.1038/s41467-021-22112-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/26/2021] [Indexed: 11/25/2022] Open
Abstract
Geomagnetic substorms are a global magnetospheric reconfiguration, during which energy is abruptly transported to the ionosphere. Central to this are the auroral electrojets, large-scale ionospheric currents that are part of a larger three-dimensional system, the substorm current wedge. Many, often conflicting, magnetospheric reconfiguration scenarios have been proposed to describe the substorm current wedge evolution and structure. SuperMAG is a worldwide collaboration providing easy access to ground based magnetometer data. Here we show application of techniques from network science to analyze data from 137 SuperMAG ground-based magnetometers. We calculate a time-varying directed network and perform community detection on the network, identifying locally dense groups of connections. Analysis of 41 substorms exhibit robust structural change from many small, uncorrelated current systems before substorm onset, to a large spatially-extended coherent system, approximately 10 minutes after onset. We interpret this as strong indication that the auroral electrojet system during substorm expansions is inherently a large-scale phenomenon and is not solely due to many meso-scale wedgelets.
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Affiliation(s)
- L Orr
- Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, UK.
| | - S C Chapman
- Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, UK
| | - J W Gjerloev
- Applied Physics Laboratory-John Hopkins University, Laurel, MD, USA
- Birkeland Centre, University of Bergen, Bergen, Norway
| | - W Guo
- School of Aerospace, Cranfield University, Cranfield, UK
- Alan Turing Institute, London, UK
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Pothier NM, Weimer DR, Moore WB. Quantitative maps of geomagnetic perturbation vectors during substorm onset and recovery. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2015; 120:1197-1214. [PMID: 26167445 PMCID: PMC4497481 DOI: 10.1002/2014ja020602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
UNLABELLED We have produced the first series of spherical harmonic, numerical maps of the time-dependent surface perturbations in the Earth's magnetic field following the onset of substorms. Data from 124 ground magnetometer stations in the Northern Hemisphere at geomagnetic latitudes above 33° were used. Ground station data averaged over 5 min intervals covering 8 years (1998-2005) were used to construct pseudo auroral upper, auroral lower, and auroral electrojet (AU*, AL*, and AE*) indices. These indices were used to generate a list of substorms that extended from 1998 to 2005, through a combination of automated processing and visual checks. Events were sorted by interplanetary magnetic field (IMF) orientation (at the Advanced Composition Explorer (ACE) satellite), dipole tilt angle, and substorm magnitude. Within each category, the events were aligned on substorm onset. A spherical cap harmonic analysis was used to obtain a least error fit of the substorm disturbance patterns at 5 min intervals up to 90 min after onset. The fits obtained at onset time were subtracted from all subsequent fits, for each group of substorm events. Maps of the three vector components of the averaged magnetic perturbations were constructed to show the effects of substorm currents. These maps are produced for several specific ranges of values for the peak |AL*| index, IMF orientation, and dipole tilt angle. We demonstrate an influence of the dipole tilt angle on the response to substorms. Our results indicate that there are downward currents poleward and upward currents just equatorward of the peak in the substorms' westward electrojet. KEY POINTS Show quantitative maps of ground geomagnetic perturbations due to substorms Three vector components mapped as function of time during onset and recovery Compare/contrast results for different tilt angle and sign of IMF Y-component.
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Affiliation(s)
- N M Pothier
- Department of Atmospheric and Planetary Sciences, Hampton UniversityHampton, Virginia, USA
- National Institute of AerospaceHampton, Virginia, USA
- Bradley Department of Electrical and Computer Engineering, Center for Space Science and Engineering Research, Virginia TechBlacksburg, Virginia, USA
- Department of Atmospheric, Oceanic, and Space Science, University of MichiganAnn Arbor, Michigan, USA
| | - D R Weimer
- National Institute of AerospaceHampton, Virginia, USA
- Bradley Department of Electrical and Computer Engineering, Center for Space Science and Engineering Research, Virginia TechBlacksburg, Virginia, USA
| | - W B Moore
- Department of Atmospheric and Planetary Sciences, Hampton UniversityHampton, Virginia, USA
- National Institute of AerospaceHampton, Virginia, USA
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Comparing the diurnal variations in the SuperMAG auroral electrojet indices SML and SMU. CHINESE SCIENCE BULLETIN-CHINESE 2014. [DOI: 10.1007/s11434-014-0451-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wang Y, Hong M, Chen G, Xu W, Du A, Zhao X, Liu X, Luo H. Nightside field-aligned current during the April 6, 2000 superstorm. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-3260-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Saetre C, Barth CA, Stadsnes J, Østgaard N, Bailey SM, Baker DN, Germany GA, Gjerloev JW. Thermospheric nitric oxide at higher latitudes: Model calculations with auroral energy input. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006ja012203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- C. Saetre
- Department of Physics and Technology; University of Bergen; Bergen Norway
| | - C. A. Barth
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - J. Stadsnes
- Department of Physics and Technology; University of Bergen; Bergen Norway
| | - N. Østgaard
- Department of Physics and Technology; University of Bergen; Bergen Norway
| | - S. M. Bailey
- Department of Electrical and Computer Engineering; Virginia Polytechnic Institute and State University; Blacksburg Virginia USA
| | - D. N. Baker
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - G. A. Germany
- Center for Space Plasma and Aeronomic Research; University of Alabama in Huntsville; Huntsville Alabama USA
| | - J. W. Gjerloev
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
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Pulkkinen A, Klimas A, Vassiliadis D, Uritsky V. Role of stochastic fluctuations in the magnetosphere-ionosphere system: A stochastic model for theAEindex variations. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011661] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pulkkinen A, Klimas A, Vassiliadis D, Uritsky V, Tanskanen E. Spatiotemporal scaling properties of the ground geomagnetic field variations. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005ja011294] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sharma AS, Baker DN, Grande M, Kamide Y, Lakhina GS, McPherron RM, Reeves GD, Rostoker G, Vondrak R, Zelenyiio L. The Storm-substorm relationship: Current understanding and outlook. DISTURBANCES IN GEOSPACE: THE STORM-SUBSTORM RELATIONSHIP 2003. [DOI: 10.1029/142gm01] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Slavin JA. Simultaneous observations of earthward flow bursts and plasmoid ejection during magnetospheric substorms. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2000ja003501] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bristow WA, Otto A, Lummerzheim D. Substorm convection patterns observed by the Super Dual Auroral Radar Network. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001ja000117] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sergeev VA, Kubyshkina MV, Liou K, Newell PT, Parks G, Nakamura R, Mukai T. Substorm and convection bay compared: Auroral and magnetotail dynamics during convection bay. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000ja900087] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sergeev VA, Kamide Y, Kokubun S, Nakamura R, Deehr CS, Hughes TJ, Lepping RP, Mukai T, Petrukovich AA, Shue JH, Shiokawa K, Troshichev OA, Yumoto K. Short-duration convection bays and localized interplanetary magnetic field structures on November 28, 1995. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98ja01747] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shiokawa K, Baumjohann W, Haerendel G, Paschmann G, Fennell JF, Friis-Christensen E, Lühr H, Reeves GD, Russell CT, Sutcliffe PR, Takahashi K. High-speed ion flow, substorm current wedge, and multiple Pi 2 pulsations. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/97ja01680] [Citation(s) in RCA: 231] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Petrukovich AA, Sergeev VA, Zelenyi LM, Mukai T, Yamamoto T, Kokubun S, Shiokawa K, Deehr CS, Budnick EY, Büchner J, Fedorov AO, Grigorieva VP, Hughes TJ, Pissarenko NF, Romanov SA, Sandahl I. Two spacecraft observations of a reconnection pulse during an auroral breakup. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/97ja02296] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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The Reaction of the Global Convection Electrojets to the Onset and Expansion of the Substorm Current Wedge. ACTA ACUST UNITED AC 1998. [DOI: 10.1007/978-94-011-4798-9_137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Lui ATY. Current disruption in the Earth's magnetosphere: Observations and models. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja00079] [Citation(s) in RCA: 447] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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