Hyperbolic decay of the Dst Index during the recovery phase of intense geomagnetic storms

Aguado, Jesus; Cid, C.; Sáiz, E.; Cerrato, Y.

doi:10.1029/2009ja014658

Cited by 28 publications

(60 citation statements)

References 60 publications

(89 reference statements)

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“…(33) becomes similar to the well-known linear equation of Burton et al (1975), which yields an exponential relaxation of W to its pre-storm level after the external driving is turned off. It is worth noting that, according to Aguado et al (2010), the magnetosphere recovers faster during first hours of the recovery phase than at later times, which implies a hyperbolic relaxation rate with L ∼ W 2 . Figure 11 (from Tsyganenko and Sitnov, 2005), shows in the top panel the dynamics of the observed and predicted variation of the SYM-H index (in the original paper the vertical axis was erroneously labeled as Dst), inferred from the TS05 model for a 12-day interval of a long double storm of 3-14 September, 2002.…”

Section: Dynamically Driven Modelsmentioning

confidence: 99%

Data-based modelling of the Earth's dynamic magnetosphere: a review

Tsyganenko

2013

Ann. Geophys.

119

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Abstract. This paper reviews the main advances in the area of data-based modelling of the Earth's distant magnetic field achieved during the last two decades. The essence and the principal goal of the approach is to extract maximum information from available data, using physically realistic and flexible mathematical structures, parameterized by the most relevant and routinely accessible observables. Accordingly, the paper concentrates on three aspects of the modelling: (i) mathematical methods to develop a computational "skeleton" of a model, (ii) spacecraft databases, and (iii) parameterization of the magnetospheric models by the solar wind drivers and/or ground-based indices. The review is followed by a discussion of the main issues concerning further progress in the area, in particular, methods to assess the models' performance and the accuracy of the field line mapping. The material presented in the paper is organized along the lines of the author Julius-Bartels' Medal Lecture during the General Assembly 2013 of the European Geosciences Union.

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Section: Dynamically Driven Modelsmentioning

confidence: 99%

Data-based modelling of the Earth's dynamic magnetosphere: a review

Tsyganenko

2013

Ann. Geophys.

119

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“…The estimated recovery was much slower than the observed one. Aguado et al (2010) proposed a hyperbolic model of storm recovery, and Cid et al (2013) applied the model to intense storms including the Carrington storm. They showed high accuracy of the hyperbolic function to reproduce the rapid recovery.…”

Section: Introductionmentioning

confidence: 99%

What caused the rapid recovery of the Carrington storm?

2015

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The geomagnetic storm during the Carrington event, which occurred on 2 September 1859, displayed extremely rapid recovery. The geomagnetic field increased by approximately 650 nT/h at Bombay, India, and by >300 nT/h in 1-h averaged data. Although the rapid recovery is considered due to a sudden increase in the magnetopause current, a sudden decrease of the ring current, or/and a sudden enhancement of the ionospheric currents, this study focuses on the ring current decay. The Carrington rapid recovery had a time constant (approximately 1 h) comparable to the storm development (i.e., decrease in the geomagnetic field), indicating that energy loss from the ring current region is predominantly controlled by E × B convection transport which is responsible for energy input during the storm main phase. This feature has led us to a hypothesis that the flow-out of dense ring current ions and injections of tenuous plasma sheet ions caused the rapid decay of the ring current and in turn the storm rapid recovery. This study examines whether the Carrington rapid recovery can be explained by the flow-out effect. We extend the empirical Burton's model to a model that takes into consideration a sudden change in solar wind density which is correlated with plasma sheet density. We first apply the extended Burton's model to previously observed four intense magnetic storms (Dst minimum < −200 nT) for which solar wind data are available. Using the best fit parameters found by forward modeling, the extended model estimates the recovery of the Carrington storm. The estimate indicates that a solar wind structure with a density bump by approximately 100 cm −3 (and southward interplanetary magnetic field (IMF) of 65 nT and solar wind speed of 1,500 km/s) can cause the rapid recovery under a continuous southward IMF condition. We conclude that the flow-out effect plays a significant role in producing the rapid recovery of the Carrington storm.

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“…Concerning the service on the prediction of the magnetosphere's recovery, it provides a graph with the theoretical expectations from the hyperbolic model introduced by Aguado et al (2010) plotted together with the Dst index from Kyoto, as soon as Dst goes below À100 nT. The code updates the graph every hour, in accordance with the resolution of the Dst index and theoretical expectations are computed until 48 h after the peak value on the index.…”

Section: Geomagnetic Predictionsmentioning

confidence: 99%

“…The UAH-Space Weather Service (UAH-SWS) at http:// www.spaceweather.es/ has been developed based on scientific models published in international journals by researchers of the UAH Saiz et al 2008;Aguado et al 2010). It is a double service: (1) it offers a warning of severe geomagnetic disturbances and (2) it provides an estimation of the time remaining for the magnetosphere to recover quiet time conditions.…”

Section: Geomagnetic Predictionsmentioning

confidence: 99%

Progress in space weather modeling in an operational environment

Tsagouri

Belehaki

Bergeot

et al. 2013

J. Space Weather Space Clim.

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This paper aims at providing an overview of latest advances in space weather modeling in an operational environment in Europe, including both the introduction of new models and improvements to existing codes and algorithms that address the broad range of space weather's prediction requirements from the Sun to the Earth. For each case, we consider the model's input data, the output parameters, products or services, its operational status, and whether it is supported by validation results, in order to build a solid basis for future developments. This work is the output of the Sub Group 1.3 ''Improvement of operational models'' of the European Cooperation in Science and Technology (COST) Action ES0803 ''Developing Space Weather Products and services in Europe'' and therefore this review focuses on the progress achieved by European research teams involved in the action.

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Hyperbolic decay of the Dst Index during the recovery phase of intense geomagnetic storms

Abstract: Abstract. What one commonly considers for reproducing the recovery phase of magnetosphere, as seen by the Dst index, is exponential function. However, the magnetosphere recovers faster in the first hours than in the late recovery phase.

Cited by 28 publications

References 60 publications

Data-based modelling of the Earth's dynamic magnetosphere: a review

Data-based modelling of the Earth's dynamic magnetosphere: a review

What caused the rapid recovery of the Carrington storm?

Progress in space weather modeling in an operational environment

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