Role of overshielding electric field on the development of pre-midnight plume event: Simulation results

Sekar, R.; Chakrabarty, D.

doi:10.1016/j.jastp.2008.04.015

Cited by 9 publications

(8 citation statements)

References 30 publications

(44 reference statements)

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“…Sudden reduction in IEFy (overshielding condition) can generate eastward electric field perturbations (upward plasma drift) over dip equator at such local times. It is verified that the out-of-phase relationship between IEFy and drift residuals was also noticed in the previous investigations [Chakrabarty et al, 2005[Chakrabarty et al, , 2006] and one such overshielding event also favored the development of plasma plume during pre-midnight hours [Sekar and Chakrabarty, 2008]. However, the in-phase relationship between drift and AE residuals during the same interval in the present case is striking and is perhaps due to substorm-related intensification of auroral electrojet current systems.…”

Section: Discussionsupporting

confidence: 90%

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Chakrabarty¹,

Sekar²,

Sastri³

et al. 2008

Geophysical Research Letters

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[1] A geomagnetic storm event is identified wherein the base of the equatorial F layer (h 0 F) over dip equator moved unusually upward till premidnight hours and descended thereafter. The h 0 F variation is linearly correlated with the variation in the smoothed auroral electrojet index (AE) which varies slowly. The fast fluctuations (residuals) with periodicity $42 min in the vertical plasma drift are found to be causally related with the fast fluctuations in the dawn-todusk component of interplanetary electric field (IEFy) and interestingly, not with the fast fluctuations in AE. However, during the interval when a substorm was triggered in association with sharp transitions in IEFy polarity, the drift fluctuations follow the AE fluctuations and are out of phase with IEFy fluctuations. The investigation demonstrates distinctive effects of IEFy and substorm-related current systems on the zonal electric field over dip equator in the premidnight hours during geomagnetic storms.

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Section: Discussionsupporting

confidence: 90%

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Chakrabarty¹,

Sekar²,

Sastri³

et al. 2008

Geophysical Research Letters

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“…The onset of equatorial spread F in the postsunset period and premidnight resurrection of plasma plume on this night were believed to be due to eastward electric field perturbations associated with the prompt penetration and overshielding effects of IEFy respectively. The role of eastward overshielding electric field in the premidnight resurrection of the plasma plume on this night was also discussed in Sekar and Chakrabarty [] based on 2‐D nonlinear numerical simulation investigations. In the work of Chakrabarty et al [], the eastward electric field perturbations due to the prompt penetration and overshielding effects separated by about an hour were shown to be associated with the southward and northward excursions of interplanetary magnetic field (IMF) B z .…”

Section: Introductionmentioning

confidence: 98%

Role of IMF B_y in the prompt electric field disturbances over equatorial ionosphere during a space weather event

et al. 2017

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On 7 January 2005 (Ap=40) prompt penetration electric field perturbations of opposite polarities were observed over Thumba and Jicamarca on a few occasions during 13:45–16:30 UT. However, the electric field was found to be eastward during 14:45–15:30 UT over both Thumba and Jicamarca contrary to the general expectation wherein opposite polarities are expected at nearly antipodal points. On closer scrutiny, three important observational features are noticed during 14:10–15:15 UT. First, during 14:10–14:45 UT, despite increasing southward interplanetary magnetic field (IMF) Bz condition, the already westward electric field over Thumba weakened (less westward) while the eastward electric field over Jicamarca intensified (more eastward). Second, the electric field not only became anomalously eastward over Thumba but also got intensified further during 14:45–15:00 UT similar to Jicamarca. Third, during 15:00–15:15 UT, despite IMF Bz remaining steadily southward, the eastward electric field continued to intensify over Thumba but weakened over Jicamarca. It is suggested that the changes in IMF By component under southward IMF Bz condition are responsible for skewing the ionospheric equipotential patterns over the dip equator in such a way that Thumba came into the same DP2 cell as that of Jicamarca leading to anomalous electric field variations. Magnetic field measurements along the Indian and Jicamarca longitude sectors and changes in high‐latitude ionospheric convection patterns provide credence to this proposition. Thus, the present investigation shows that the variations in IMF By are fundamentally important to understand the prompt penetration effects over low latitudes.

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“…During geomagnetic disturbances, low latitude ionosphere gets affected by several types of electric fields perturbations: prompt electric field perturbations associated with magnetospheric convection (e.g., Chakrabarty et al., ; Jaggi & Wolf, ; Tsurutani et al., ), substorm (Chakrabarty et al., ; Hashimoto et al., , ; Huang, ), overshielding‐OS (Hashimoto et al., ; Kikuchi et al., ; Sekar & Chakrabarty, ), ram pressure (Huang et al., ; Rout et al., ), and delayed electric field perturbations due to disturbance dynamo‐DD (e.g., Blanc & Richmond, ; Fejer & Emmert, ; Maruyama et al., ; Pandey et al., ). During southward conditions of Interplanetary Magnetic Field (IMF) Bz, the effects of the fast fluctuations in the Y component (dawn‐dusk) of solar wind/interplanetary electric field (IEFy) can reach up to low‐equatorial latitudes as the time constant of the shielding region at the inner edge of the ring current is much larger than the time constant associated with the magnetospheric convection.…”

Section: Introductionmentioning

confidence: 99%

Significant Electric Field Perturbations in Low Latitude Ionosphere due to the Passage of Two Consecutive ICMEs During 6–8 September 2017

et al. 2019

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This investigation shows that the significant electric field disturbances in the dip‐equatorial ionosphere during the geomagnetic storm of 6–8 September 2017 are due to the passage of two consecutive interplanetary coronal mass ejections (ICMEs). During the passage of the first ICME sheath, a long duration (∼10 hr) prompt penetration (PP) event is operational in which 60‐min periodic component is found to be present in vertical drift as well as in equatorial electrojet, but the 45‐min periodicity, though present, is not significant in equatorial electrojet. On 8 September, the shock associated with the second ICME enhances the F region vertical plasma drift to ∼150 m/s in the evening hours which is one of the highest vertical drift ever measured over Jicamarca. The same PP electric field causes unusually large enhancement of the equatorial electrojet strength to ∼135 nT in the early morning hours over the Philippine sector. The disturbance dynamo (DD) that follows the storm causes an upward vertical drift of ∼55 m/s during postmidnight hours over Jicamarca which is one of the highest observed. These unusually large electric field perturbations cause significant changes in the F region plasma fountain. It is shown that these electric field perturbations cannot be accounted by PP/DD electric field associated with the geomagnetic storm only and significant contribution from substorm is conspicuous. Therefore, the present investigation highlights the need to evaluate the role of substorm in unusually large electric field perturbations over equatorial ionosphere.

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Role of overshielding electric field on the development of pre-midnight plume event: Simulation results

Cited by 9 publications

References 30 publications

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Role of IMF B_y in the prompt electric field disturbances over equatorial ionosphere during a space weather event

Significant Electric Field Perturbations in Low Latitude Ionosphere due to the Passage of Two Consecutive ICMEs During 6–8 September 2017

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Role of overshielding electric field on the development of pre-midnight plume event: Simulation results

Cited by 9 publications

References 30 publications

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Distinctive effects of interplanetary electric field and substorm on nighttime equatorial F layer: A case study

Role of IMF By in the prompt electric field disturbances over equatorial ionosphere during a space weather event

Significant Electric Field Perturbations in Low Latitude Ionosphere due to the Passage of Two Consecutive ICMEs During 6–8 September 2017

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Role of IMF B_y in the prompt electric field disturbances over equatorial ionosphere during a space weather event