Timing of magnetic reconnection initiation during a global magnetospheric substorm onset

Baker, D. N.; Peterson, W. K.; Eriksson, S.; Li, X.; Blake, J. B.; Burch, J. L.; Daly, P. W.; Dunlop, M. W.; Korth, A.; Donovan, E.; Friedel, R.; Fritz, T. A.; Frey, H. U.; Mende, S. B.; Roeder, J. L.; Singer, H. J.

doi:10.1029/2002gl015539

Cited by 110 publications

(169 citation statements)

References 16 publications

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“…This mechanism is consistent with the motion of auroral enhancement (known as auroral breakup) traveling northward and westward (Akasofu, 1964;Baker et al, 2002;Henderson et al, 2006). Moreover, whether there is only a sequence of auroral pseudobreakups or a full substorm expansion, manifested by the dramatic brightening of auroral features, directly depends on the occurrence frequency of flux ropes moving earthward and consequently their ability of temporarily or permanently disrupting the cross-tail current.…”

Section: Discussionsupporting

confidence: 53%

Dipolarization fronts in the near-Earth space and substorm dynamics

et al. 2015

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Abstract. During magnetospheric substorms and plasma transport in the Earth's magnetotail various magnetic structures can be detected. Dipolarization fronts and flux ropes are the most prominent structures characteristic for substorm dynamics. However, they are treated as separate magnetotail features independent of each other. In this paper, we analyze a number of dipolarization fronts observed by the THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft at different geocentric distances by applying the magnetohydrostatic Grad-Shafranov (GS) reconstruction technique. Our analysis shows that there is a possibility of dipolarization fronts to originate from highly dissipated flux ropes which are in the late stage of their evolution, subjected to a continuous magnetic deterioration due to the reconnection process. These results may improve our understanding of magnetoplasma processes in Earth's magnetotail.

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Section: Discussionsupporting

confidence: 53%

Dipolarization fronts in the near-Earth space and substorm dynamics

et al. 2015

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“…The Blake et al (2005) paper showed a linkage for the mid 10's to 100's keV electron fluxes between geosynchronous altitude and the Polar, Chandra, and Cluster satellite apogee altitudes (all well outside of geosynchronous) on the night side during one substorm. Other authors have shown similar results (e.g., Baker et al, 2002). There are still some questions about the relative timing of the arrival of such source or seed populations and the observed onsets of reconnection in the magnetotail.…”

Section: Source Populationssupporting

confidence: 72%

“…It is thought that these electrons are brought into the inner magnetosphere, to geosynchronous and lower altitudes, from the near-Earth magnetotail by substorm injections and the storm-time convection that also brings the ring current ions into the inner magnetosphere (Baker et al, 2002;Blake et al. 2005;Jordanova, 2003.…”

Section: Source Populationsmentioning

confidence: 99%

Evolution and Energization of Energetic Electrons in the Inner Magnetosphere

Fennell

Roeder

2009

Astrophysics and Space Science Proceedings

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0186), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MU-YYYY) 15- SMC SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTA review is presented of what we know about the evolution and energization of energetic electrons in the inner magnetosphere. We emphasize what we have learned since the review by Friedel et al. (2002) with the primary result being a greater focus on local acceleration processes and significant new evidence that points to processes that are acting in the region between GPS and geosynchronous altitudes. We use as an example the magnetosphere's energetic electron responses to storms that occurred in the 16-25 July 2004 period. They had increasing magnitude in terms of minimum D ST of-80,-101 ,-148, and -197 nT. We examined the penetration and enhancements of the electrons as a function of L. We found that the smallest storms did not cause relativistic electron enhancements for L < 6.5, but did cause enhancements in the "source" populations at > 130 and >230 keV down to L ~ 3.0. The results indicate that the electron fluxes observed at Cluster may be directly linked to the rapid response of electrons at low L observed by HE03, and could have been the source for the <1 MeV fluxes. SUBJECT TERMS Acknowledgment;The authors would like to acknowledge their many colleagues at The Aerospace Corporation that have supported their efforts, provided references, and participated in discussions on the topic of energetic electron sources and process in the magnetosphere.

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“…Various timing analyses have been performed to try and identify the initiator of the magnetospheric substorm (e.g. Kepko et al, 2004;Baker et al, 2002;Ohtani et al, 1999). Whilst Ohtani et al (1999) suggest that current disruption need not follow directly from NENL formation, Kepko et al (2004) and Baker et al (2002) conclude that a flow-burst driven model, i.e.…”

Section: Introductionmentioning

confidence: 99%

Thinning and expansion of the substorm plasma sheet: Cluster PEACE timing analysis

et al. 2004

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Abstract. The storage and subsequent removal of magnetic flux in the magnetotail during a geomagnetic substorm has a dramatic effect on the thickness of the cross-tail plasma sheet. The near-Earth plasma sheet is thought to thin during the growth phase and then rapidly expand after onset of the substorm. The direction of propagation, whether earthward or tailward along the GSM-X direction in the near-Earth tail, may suggest the time ordering of current-disruption and near-Earth reconnection, both of which are key to the substorm process. Cluster's Plasma Electron And Current Experiment (PEACE) allows 4-point observations of electrons at the plasma sheet -lobe boundary as this interface passes over the Cluster tetrahedron. The relative timings of the boundary passage at each spacecraft allow a determination of this boundary's speed and direction of motion, assuming this is planar on the scale of the Cluster separation scale. For those boundaries corresponding to the expansion of the plasma sheet, this direction is fundamental to determining the direction of expansion. We present an example of isolated thinning and expansion of the plasma sheet, as well as a multiple thinning-expansion event that occurs during a more active substorm. Data from the 2001 and 2002 tail passes have been analysed and the average plasma sheet -lobe boundary normal vectors and normal component velocities have been calculated. A total of 77 crossings, typically between 10 and 20 R E downtail, correspond to substorm associated expansion of the plasma sheet over the spacecraft. These had normal vectors predominantly in the GSM-YZ plane and provided no clear evidence for the formation of the near-Earth neutral line occurring before current disruption or vice versa. The expansions of the plasma sheet generally exhibit the appropriate GSM-Z direction expected for the given lobe, and tend to have GSM-Y components that support onset occurring near the origin of the GSM-YZ plane. This result is noteworthy in that it indicates a homogeneous plasma sheet expansion. These expansions have an average velocity along their normal of 60±37 km s −1 . Conversely we find an average thinning velocity of 43±32 km s −1 from 66 substormCorrespondence to: J. P. Dewhurst (jpd@mssl.ucl.ac.uk) associated thinnings. The normal vectors of the thinning plasma sheet vary considerably in the GSM-YZ plane across the entire magnetotail, suggesting that more complex dynamics govern this process.

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Timing of magnetic reconnection initiation during a global magnetospheric substorm onset

Cited by 110 publications

References 16 publications

Dipolarization fronts in the near-Earth space and substorm dynamics

Dipolarization fronts in the near-Earth space and substorm dynamics

Evolution and Energization of Energetic Electrons in the Inner Magnetosphere

Thinning and expansion of the substorm plasma sheet: Cluster PEACE timing analysis

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