Computer simulation of inner magnetospheric dynamics for the magnetic storm of July 29, 1977

Wolf, R. A.; Harel, M.; Spiro, R. W.; Voigt, G. H.; Reiff, P. H.; Chen, C.-K.

doi:10.1029/ja087ia08p05949

Cited by 176 publications

(117 citation statements)

References 37 publications

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“…Another widely used inner magnetosphere model is the Rice Convection Model (RCM), which describes plasma electrodynamics in the inner and middle magnetosphere and its coupling to the ionosphere (Wolf et al, 1982;Spiro et al, 1981). The RCM represents the plasma distribution in terms of multiple fluids.…”

Section: Introductionmentioning

confidence: 99%

Storm-time ring current: model-dependent results

2012

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Abstract. The main point of the paper is to investigate how much the modeled ring current depends on the representations of magnetic and electric fields and boundary conditions used in simulations. Two storm events, one moderate (SymH minimum of −120 nT) on 6-7 November 1997 and one intense (SymH minimum of −230 nT) on 21-22 October 1999, are modeled. A rather simple ring current model is employed, namely, the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM), in order to make the results most evident. Four different magnetic field and two electric field representations and four boundary conditions are used. We find that different combinations of the magnetic and electric field configurations and boundary conditions result in very different modeled ring current, and, therefore, the physical conclusions based on simulation results can differ significantly. A time-dependent boundary outside of 6.6 R E gives a possibility to take into account the particles in the transition region (between dipole and stretched field lines) forming partial ring current and near-Earth tail current in that region. Calculating the model SymH* by Biot-Savart's law instead of the widely used Dessler-Parker-Sckopke (DPS) relation gives larger and more realistic values, since the currents are calculated in the regions with nondipolar magnetic field. Therefore, the boundary location and the method of SymH* calculation are of key importance for ring current data-model comparisons to be correctly interpreted.

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Section: Introductionmentioning

confidence: 99%

Storm-time ring current: model-dependent results

2012

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“…The RCM has been used to simulate prompt penetration electric fields and they have been compared with observations over a period of many years (e.g., Wolf et al, 1982;Spiro et al, 1988) to validate the model. The model calculates the ionospheric electric potential equatorward of the polar cap boundary by taking into account the self-consistent magnetosphere-ionosphere coupling, in response to polar cap potential variations specified at the boundary.…”

Section: Coupled Ctip-rcm Modelmentioning

confidence: 99%

“…But a sudden increase (decrease) in the strength of the convection field most commonly caused by southward (northward) turnings of the interplanetary magnetic field (IMF) B z component, can occur faster than the ring current particles can reconfigure itself in response to the driving field to shield the low-and mid-latitude ionosphere. Thus an excess electric field can appear in the mid-and lowlatitude regions that is referred to as an undershielding (overshielding) condition (e.g., Wolf et al, 1982;Kelley, 1989) and is sometime referred to as a penetration field. On the dayside of the Earth this penetration electric field during undershielding condition produces an excess eastward electric field near the equator that in turn causes an excess E × B upward motion of the ions in the ionosphere.…”

Section: Introductionmentioning

confidence: 99%

Storm-time meridional flows: a comparison of CINDI observations and model results

et al. 2014

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Abstract. During a large geomagnetic storm, the electric field from the polar ionosphere can expand far enough to affect the mid-latitude and equatorial electric fields. These changes in the equatorial zonal electric field, called the penetration field, will cause changes in the meridional ion flows that can be observed by radars and spacecraft. In general this E × B ion flow near the equator caused by the penetration field during undershielding conditions will be upward on the dayside and downward on the nightside of the Earth. Previous analysis of the equatorial meridional flows observed by CINDI instrument on the C/NOFS spacecraft during the 26 September 2011 storm showed that all of the response flows on the dayside were excess downward flows instead of the expected upward flows. These observed storm-time responses are compared to a prediction from a physics-based coupled model of thermosphere-ionosphereinner-magnetosphere in an effort to explain these observations. The model results suggest that the equatorial downward flow could be attributed to a combined effect of the overshielding and disturbance dynamo processes. However, some discrepancy between the model and observation indicates a need for improving our understanding of how sensitive the equatorial electric field is to various model input parameters that describe the magnetosphere-ionosphere coupling processes.

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“…Furthermore, the plasma sheet is believed to be one of the major particle source for the ring current population (10-200 keV ions and electrons) (Chen et al, 1994;Jordanova et al, 1998;Kozyra et al, 1998;Wang et al, 2008). For this reason many ring current simulations have used the plasma sheet properties as an outer boundary condition for their calculations (Wolf et al, 1982;Chen et al, 1994;Fok et al, 1996;Kozyra et al, 1998;Ebihara et J. B. Cao et al: The statistical studies of the inner boundary of plasma sheet Ganushkina et al, 2005;Jordanova and Miyoshi, 2005;Liemohn et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

The statistical studies of the inner boundary of plasma sheet

et al. 2011

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Abstract. The penetration of plasma sheet ions into the inner magnetosphere is very important to the inner magnetospheric dynamics since plasma sheet ions are one of the major particle sources of ring current during storm times. However, the direct observations of the inner boundary of the plasma sheet are fairly rare due to the limited number of satellites in near equatorial orbits outside 6.6 R E . In this paper, we used the ion data recorded by TC-1 from 2004 to 2006 to study the distribution of inner boundary of ion plasma sheet (IBIPS) and for the first time show the observational distribution of IBIPS in the equatorial plane. The IBIPS has a dawn-dusk asymmetry, being farthest to the Earth in the 06:00 08:00 LT bin and closest to the Earth in the 18:00-20:00 LT bin. Besides, the IBIPS has also a day-night asymmetry, which may be due to the fact that the ions on the dayside are exposed more time to loss mechanisms on their drift paths. The radial distance of IBIPS decrease generally with the increase of Kp index. The mean radial distance of IBIPS is basically larger than 6.6 R E during quiet times and smaller than 6.6 R E during active times. When the strength of convection electric field increases, the inward shift of IBIPS is most significant on the night side (22:00-02:00 LT). For Kp ≤ 0 + , only 16% of IBIPSs penetrate inside the geosynchronous orbit. For 2 ≤ Kp < 3 + , however, 70% of IBIPSs penetrate inside the geosynchronous orbit. The IBIPS has weak correlations with the AE and Dst indexes. The average correlation coefficient between R i and Kp is −0.58 while the correlation coefficient between R i and AE/Dst is only −0.29/0.17. The correlation coefficients are local time dependent. Particularly, R i and Kp are highly correlated (r = −0.72) in the night sector, meaning that the radial distance of IBIPS R i in the night sector hasCorrespondence to: J. B. Cao (jbcao@cssar.ac.cn) the good response to the Kp index These observations indicate that Kp plays a key role in determining the position of IBIPS.

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Computer simulation of inner magnetospheric dynamics for the magnetic storm of July 29, 1977

Cited by 176 publications

References 37 publications

Storm-time ring current: model-dependent results

Storm-time ring current: model-dependent results

Storm-time meridional flows: a comparison of CINDI observations and model results

The statistical studies of the inner boundary of plasma sheet

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