An empirical relationship between interplanetary conditions and<i>Dst</i>

Burton, Rande K.; McPherron, R. L.; Russell, C. T.

doi:10.1029/ja080i031p04204

Cited by 1,279 publications

(1,401 citation statements)

References 23 publications

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“…However, storms occur generally when the interplanetary magnetic field (IMF) is strong and steady and not in intervals of fluctuating IMF (Russell et al, 1974;Russell et al, 2000). Using what was understood about the control of the reconnection by the IMF, Burton et al (1975) demonstrated that the ring current could be predicted from solar wind parameters with an extremely simple prescription. Energy is injected into the ring current at a rate proportional to the amount of convected southward IMF (i.e.…”

Section: Introductionmentioning

confidence: 99%

Morphology of the ring current derived from magnetic field observations

2004

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Abstract. Our examination of the 20 years of magnetospheric magnetic field data from ISEE, AMPTE/CCE and Polar missions has allowed us to quantify how the ring current flows and closes in the magnetosphere at a variety of disturbance levels. Using intercalibrated magnetic field data from the three spacecraft, we are able to construct the statistical magnetic field maps and derive 3-dimensional current density by the simple device of taking the curl of the statistically determined magnetic field. The results show that there are two ring currents, an inner one that flows eastward at ∼3 R E and a main westward ring current at ∼4-7 R E for all levels of geomagnetic disturbances. In general, the insitu observations show that the ring current varies as the D st index decreases, as we would expect it to change. An unexpected result is how asymmetric it is in local time. Some current clearly circles the magnetosphere but much of the energetic plasma stays in the night hemisphere. These energetic particles appear not to be able to readily convect into the dayside magnetosphere. During quiet times, the symmetric and partial ring currents are similar in strength (∼0.5 MA) and the peak of the westward ring current is close to local midnight. It is the partial ring current that exhibits most drastic intensification as the level of disturbances increases. Under the condition of moderate magnetic storms, the total partial ring current reaches ∼3 MA, whereas the total symmetric ring current is ∼1 MA. Thus, the partial ring current contributes dominantly to the decrease in the D st index. As the ring current strengthens the peak of the partial ring current shifts duskward to the pre-midnight sector. The partial ring current is closed by a meridional current system through the ionosphere, mainly the field-aligned current, which maximizes at local times near the dawn and dusk. The closure currents flow in the sense of region-2 field-aligned currents, downward into the ionosphere near the dusk and upward out of the ionosphere near the dawn.

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Section: Introductionmentioning

confidence: 99%

Morphology of the ring current derived from magnetic field observations

2004

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“…As well known the main source of magnetospheric disturbances including the magnetic storms is the southward component B z of interplanetary magnetic field (IMF) [Dungey, 1961;Fairfield and Cahill Jr, 1966;Rostoker and Falthammar, 1967;Russell et al, 1974;Burton et al, 1975;Akasofu, 1981]. In the steady types of the SW streams the IMF lies near the ecliptic plane, and these types are not geoeffective.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of large‐scale solar wind streams obtained by the double superposed epoch analysis

et al. 2015

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Using the OMNI data for period 1976-2000 we investigate the temporal profiles of 20 plasma and field parameters in the disturbed large-scale types of solar wind (SW): CIR, ICME (both MC and Ejecta) and Sheath as well as the interplanetary shock (IS). To take into account the different durations of SW types we use the double superposed epoch analysis (DSEA) method: re-scaling the duration of the interval for all types in such a manner that, respectively, beginning and end for all intervals of selected type coincide. As the analyzed SW types can interact with each other and change parameters as a result of such interaction, we investigate separately 8 sequences of SW types: (1) CIR, (2) IS/CIR, (3) Ejecta, (4) Sheath/Ejecta, (5) IS/Sheath/Ejecta, (6) MC, (7) Sheath/MC, and ( 8) IS/Sheath/MC. The main conclusion is that the behavior of parameters in Sheath and in CIR are very similar both qualitatively and quantitatively. Both the high-speed stream (HSS) and the fast ICME play a role of pistons which push the plasma located ahead them. The increase of speed in HSS and ICME leads at first to formation of compression regions (CIR and Sheath, respectively), and then to IS. The occurrence of compression regions and IS increases the probability of growth of magnetospheric activity.

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“…During the positive B z IMF the F -layer cannot rise up 350 km for the generation of scintillations. As shown by Burton et al (1975), Sizova and Zaitseva (1984), Pudovkin at al. (1985) the magnetospheric ring current intensity is strongly dependent on the variations of the B z IMF.…”

Section: Discussionmentioning

confidence: 84%

Role of the magnetospheric and ionospheric currents in the generation of the equatorial scintillations during geomagnetic storms

Biktash

2004

Ann. Geophys.

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Abstract. The equatorial ionosphere parameters, K p , D st , AU and AL indices characterized contribution of different magnetospheric and ionospheric currents to the Hcomponent of geomagnetic field are examined to test the geomagnetic activity effect on the generation of ionospheric irregularities producing VLF scintillations. According to the results of the current statistical studies, one can predict near 70% of scintillations from Aarons' criteria using the D st index, which mainly depicts the magnetospheric ring current field. To amplify Aarons' criteria or to propose new criteria for predicting scintillation characteristics is the question. In the present phase of the experimental investigations of electron density irregularities in the ionosphere new ways are opened up because observations in the interaction between the solar wind -magnetosphere -ionosphere during magnetic storms have progressed greatly. According to present view, the intensity of the electric fields and currents at the polar regions, as well as the magnetospheric ring current intensity, are strongly dependent on the variations of the interplanetary magnetic field. The magnetospheric ring current cannot directly penetrate the equatorial ionosphere and because of this difficulties emerge in explaining its relation to scintillation activity. On the other hand, the equatorial scintillations can be observed in the absence of the magnetospheric ring current. It is shown that in addition to Aarons' criteria for the prediction of the ionospheric scintillations, models can be used to explain the relationship between the equatorial ionospheric parameters, h F , f oF 2, and the equatorial geomagnetic variations with the polar ionosphere currents and the solar wind.

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An empirical relationship between interplanetary conditions andDst

Cited by 1,279 publications

References 23 publications

Morphology of the ring current derived from magnetic field observations

Morphology of the ring current derived from magnetic field observations

Dynamics of large‐scale solar wind streams obtained by the double superposed epoch analysis

Role of the magnetospheric and ionospheric currents in the generation of the equatorial scintillations during geomagnetic storms

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