Two spacecraft observations of a reconnection pulse during an auroral breakup

Petrukovich, A. A.; Сергеев, В. А.; Zelenyǐ, L. M.; Mukai, T.; Yamamoto, T.; Kokubun, S.; Shiokawa, K.; Deehr, C. S.; Budnick, E.; Büchner, Jörg; Fedorov, A.; Grigorieva, V. P.; Hughes, T. J.; Pissarenko, N. F.; Романов, С. А.; Sandahl, I.

doi:10.1029/97ja02296

Cited by 92 publications

(64 citation statements)

References 27 publications

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“…Concerning the role of reconnection and its location, our results agree with those of Petrukovich et al (1998), who determined the location of the reconnection site during the pseudobreakup to be rather close to the Earth (at ∼16 R E ). Nagai et al (1998) also reported on the reconnection event which started at X > −15R E during the pseudobreakup.…”

Section: Comparison With Previous Observationssupporting

confidence: 82%

Correlated Interball/ground-based observations of isolated substorm: The pseudobreakup phase

et al. 2001

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Abstract. We study the isolated substorm that occurred after a long quiet period, which showed all of the substorm signatures except for the first half hour of the expansion phase, which could be characterized as a pseudobreakup sequence, rather than a full-scale substorm onset. During the considered event, the substorm's instability leads to a current disruption, which starts at the near-Earth plasma sheet and then propagates tailward. Based on auroral observations, the analysis of geosynchronous plasma injections, and the plasma sheet observations at ∼15 R E at the meridian of auroral substorm development we show that (1) before and probably during "pseudobreakup phase", the plasma sheet stayed cold and dense, (2) during the pseudobreakup phase, particle injections at 6.6 R E were only seen in unusually low energy components, and (3) the electron precipitation into the ionosphere was very soft. We conclude that the basic difference between pseudobreakups and "real" substorm activations was found in the low energy of all manifestations. We suggest that high density and low electron temperature in the plasma sheet are the reasons for low energization in the magnetic reconnection operated on closed field lines in the plasma sheet, as well as the weak field-aligned acceleration, as predicted by the Knight's relationship. The low Hall conductivity could then be the reason for the weak ground magnetic effects observed. This explanation suggests that the role of the ionospheric conductivity is "passive" as the plasma sheet, rather than the ionosphere, controls the development of the magnetospheric instability.

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Section: Comparison With Previous Observationssupporting

confidence: 82%

Correlated Interball/ground-based observations of isolated substorm: The pseudobreakup phase

et al. 2001

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“…Even the substructure of characteristically pulsed dayside reconnection on 5-10 min time scales (i.e. flux transfer events) are well-resolved in dayside flow data as pulsed ionospheric flows (Lockwood et al, 1989(Lockwood et al, , 1993Elphic et al, 1990;Pinnock et al, 1993Pinnock et al, , 1995Moen et al, 1995;Provan et al, 1998;Neudegg et al, 1999Neudegg et al, , 2000Milan et al, 2000;Wild et al, 2001). As a consequence, there is now little uncertainty about the central role of magnetopause reconnection in magnetospheric dynamics and flow excitation.…”

Section: Introductionmentioning

confidence: 96%

“…Lui, 1991Lui, , 1996Frank and Sigwarth, 2000;Friedrich et al, 2001). Nevertheless, recent results from the Geotail spacecraft do show that reconnection typically begins in the dusk sector plasma sheet at down-tail distances of ∼20-30 R E , a few minutes before the onset of expansion signatures on the ground, and then expands to encompass a significant fraction of the dusk and midnight sector tail (Nagai et al, 1998; Nagai and Machida, 1998; Petrukovich et al, 1998;Machida et al, 1999). Both initial dipolarization and the convection that results from tail reconnection contribute to substorm-associated Dungey-cycle flux transport in the tail.…”

Section: Introductionmentioning

confidence: 99%

Excitation of twin-vortex flow in the nightside high-latitude ionosphere during an isolated substorm

et al. 2002

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Abstract. We present SuperDARN radar observations of the ionospheric flow during a well-observed high-latitude substorm which occurred during steady northward IMF conditions on 2 December 1999. These data clearly demonstrate the excitation of large-scale flow associated with the substorm expansion phase, with enhanced equatorward flows being observed in the pre-midnight local time sector of the expansion phase auroral bulge and westward electrojet, and enhanced return sunward flows being present at local times on either side, extending into the dayside sector. The flow pattern excited was thus of twin-vortex form, with foci located at either end of the substorm auroral bulge, as imaged by the Polar VIS UV imager. Estimated total transpolar voltages were ∼40 kV prior to expansion phase onset, grew to ∼80 kV over a ∼15 min interval during the expansion phase, and then decayed to ∼35 kV over ∼10 min during recovery. The excitation of the large-scale flow pattern resulted in the development of magnetic disturbances which extended well outside of the region directly disturbed by the substorm, depending upon the change in the flow and the local ionospheric conductivity. It is estimated that the nightside reconnection rate averaged over the 24-min interval of the substorm was ∼65-

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“…Further elaboration of this hypothesis resulted in creating space weather forecasting tools based on local-linear filters (Price et al, 1994;Vassiliadis et al, 1995;Valdivia et al, 1996), data-derived analogues (Klimas et al, 1997;Horton et al, 1999), and neural networks (Hernandes et al, 1993;Gleisner and Lundstedt, 1997;Weigel et al, 2002). The low dimensional organized behavior of the magnetosphere on global scales is also evident in many in situ observations of the large-scale features of substorms by many spacecrafts including INTERBALL and GEOTAIL missions (Petrukovich et al, 1998;Nagai et al, 1998;Ieda et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Combining global and multi-scale features in a description of the solar wind-magnetosphere coupling

et al. 2003

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Abstract. The solar wind-magnetosphere coupling during substorms exhibits dynamical features in a wide range of spatial and temporal scales. The goal of our work is to combine the global and multi-scale description of magnetospheric dynamics in a unified data-derived model. For this purpose we use deterministic methods of nonlinear dynamics, together with a probabilistic approach of statistical physics. In this paper we discuss the mathematical aspects of such a combined analysis. In particular we introduce a new method of embedding analysis based on the notion of a mean-field dimension. For a given level of averaging in the system the mean-filed dimension determines the minimum dimension of the embedding space in which the averaged dynamical system approximates the actual dynamics with the given accuracy. This new technique is first tested on a number of wellknown autonomous and open dynamical systems with and without noise contamination. Then, the dimension analysis is carried out for the correlated solar wind-magnetosphere database using vB S time series as the input and AL index as the output of the system. It is found that the minimum embedding dimension of vB S − AL time series is a function of the level of ensemble averaging and the specified accuracy of the method. To extract the global component from the observed time series the ensemble averaging is carried out over the range of scales populated by a high dimensional multiscale constituent. The wider the range of scales which are smoothed away, the smaller the mean-field dimension of the system. The method also yields a probability density function in the reconstructed phase space which provides the basis for the probabilistic modeling of the multi-scale dynamical features, and is also used to visualize the global portion of the solar wind-magnetosphere coupling. The structure of its input-output phase portrait reveals the existence of two energy levels in the system with non-equilibrium dynamical features such as hysteresis which are typical for non-equilibrium phase transitions. Further improvements in space weather forecasting tools may be achieved by a combiCorrespondence to: A. Y. Ukhorskiy (sasha@astro.umd.edu) nation of the dynamical description for the global component and a statistical approach for the multi-scale component.

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Two spacecraft observations of a reconnection pulse during an auroral breakup

Cited by 92 publications

References 27 publications

Correlated Interball/ground-based observations of isolated substorm: The pseudobreakup phase

Correlated Interball/ground-based observations of isolated substorm: The pseudobreakup phase

Excitation of twin-vortex flow in the nightside high-latitude ionosphere during an isolated substorm

Combining global and multi-scale features in a description of the solar wind-magnetosphere coupling

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