On the Nocturnal Downward and Westward Equatorial Ionospheric Plasma Drifts During the 17 March 2015 Geomagnetic Storm

Bagiya, Mala S.; Vichare, Geeta; Sinha, A. K.; Sripathi, S.

doi:10.1002/2017ja024703

Cited by 6 publications

(11 citation statements)

References 41 publications

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“…But, the same may not be applicable to other regions, so unlike Bagiya et al. (2018), we avoid using the hypothesis of Abdu et al. (1998) to explain the observed effect.…”

Section: Discussionmentioning

confidence: 94%

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Spatial and Temporal Confinement of the Ionospheric Responses During the St. Patrick's Day Storm of March 2015

Kader

Dashora

Niranjan³

2022

Space Weather

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The present study provides a multi‐instrument analysis of the ionospheric response to the effects of the St. Patrick's Day storm of 17–18 March 2015. Simultaneous observations from 85 global positioning system stations and multiple satellites along the past observations from the literature survey are utilized to ascertain the spatio‐temporal confinements between −20°E and 150°E longitudes. The main results include longitudinal differences in the episodic equatorward expansions of the auroral oval which is shown to relate with varying high‐latitude Joule heating and equatorward wind surges at different local times. The zonal movement of equatorial ion density depletions from initially east to west followed by a sluggish westward pattern on the night of 17 March is observed. The zonal movement is found to be better explained by the longitudinally decreasing impact of the disturbance dynamo in the nightside. The enhancements in total electron content during morning on 17 March are observed over mid‐latitudes, which are found to move equatorward in the noon time. These enhancements could be associated with the enhanced O density bulge resulting from the thermospheric expansion during the main phase. A daytime sustained and confined electron density depletion between about 100°E and 170°E is observed on 18 March which is being discussed in detail for the first time. Interestingly, large longitudinal differences are observed in the response of the disturbance dynamo, including no observable effect during morning (−20°E–20°E) but dominant afternoon and westward progression during the day of 18 March.

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“…But, the same may not be applicable to other regions, so unlike Bagiya et al. (2018), we avoid using the hypothesis of Abdu et al. (1998) to explain the observed effect.…”

Section: Discussionmentioning

confidence: 94%

“…Bagiya et al. (2018) have shown that the zonal drift of the irregularities in the Indian sector on the night of 17 March fluctuated from initial eastward to westward (at ∼1630 UT) and again eastward at ∼18 UT, eventually varying at small westward amplitude till 21 UT.…”

Section: Discussionmentioning

confidence: 99%

Spatial and Temporal Confinement of the Ionospheric Responses During the St. Patrick's Day Storm of March 2015

Kader

Dashora

Niranjan³

2022

Space Weather

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“…6.5°N) show westward drift of irregularity after 21:45 IST (IST = Indian Standard Time = UTC + 5:30 Hr), on 17 March 2015 (Patra et al., 2016). Observation from spaced GNSS receivers, located in Tirunelveli (8.73°N, 77.70°E; mag.0.32°N), show reversal of zonal irregularity drift during 16:30–18:00 UT (22:00–23:30 IST) of 17 March 2015 (Bagiya et al., 2018). Considering a westward drift was reported from 77°E (Tirunelveli) at 22:00 IST and from 79°E (Gadanki) at 21:45 IST, it can be conjectured to have reached Calcutta (88°E) at an earlier time.…”

Section: Discussionmentioning

confidence: 99%

“…Some of the previous studies have reported presence of westward electric field during day-time of a geomagnetic disturbed period, leading to reduction in eastward electric field and hence inhibition in the height of Equatorial Ionization Anomaly (EIA) and h m F 2 , which was restricted over a limited longitude sector (Taiwan) BISWAS AND PAUL 10.1029/2023RS007669 4 of 16 (Kalita et al, 2016;Nayak et al, 2017;Rajesh et al, 2017). Ample previous studies have also reported reversal of night-time irregularity drift in the equatorial region, during an intense geomagnetic storm (Bagiya et al, 2018;de Paula et al, 2019;Kader et al, 2022;Patra et al, 2016). Therefore, in this study, efforts have also been made to investigate the effect of westward drifting irregularity, occurring during a geomagnetically disturbed day, on signal loss-of-lock when the zonal velocity component of the satellite was also westward.…”

Section: Biswas and Paulmentioning

confidence: 95%

Effects of the Relative Dynamics of Ionospheric Irregularities and GPS Satellites on Receiver Tracking Loop Performance

Biswas,

Paul

2023

Radio Science

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Transionospheric satellite signals are exposed to perturbation, caused by irregularities generated in the ionosphere. However, the characteristics of the satellite motion can have an additional impact on signal perturbation, in addition to the effects of irregularity structures, that drift from west to east during geomagnetic quiet conditions. This paper reports the effect of GPS satellite geometry, on tracking loop performance of ground‐based receivers, during occurrence of ionospheric scintillations. Observations are made from station Calcutta (22.58° N, 88.38° E geographic; magnetic dip 34.54°), located near the northern crest of Equatorial Ionization Anomaly (EIA), during three different solar activity periods (March 2014, March 2015 and March 2022). Efforts have been made to study the correlation of east‐west component of satellite velocity at Ionospheric Pierce Point (IPP) with duration of loss‐of‐lock and rate of signal fading (< ‐10 dB), from ground scintillation pattern observations. Results of this study show 75‐78% correlation between duration of loss‐of‐lock and eastward component of satellite velocity, for all three period of observation. Subsequently, shorter duration of loss‐of‐lock has been observed corresponding to satellite velocity being westward. Signal fading rate is found to decrease with increasing satellite velocity, having median value of the fading rate cumulative distribution percentage, corresponding to satellite velocity of 16.69 m/s, 31.76 m/s and 19.14 m/s respectively during March 2014, March 2015 and March 2022. Results of this study also indicate direction and component of satellite velocity at IPP to be a dominant cause of signal outage, even during periods of weak to moderate scintillations.

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“…Most of the studies on ionospheric response to solar flares pertain to periods during which either the effects of geomagnetic storms were not yet prevailed or the flare events were not accompanied by geomagnetic storms. The effects of geomagnetic storms over low-latitude ionosphere can be understood through electrodynamic (penetration of storm induced electric fields) and neutral dynamic (storm induced thermospheric neutral composition changes) coupling between high and low latitude ionosphere (e.g., Bagiya et al, 2011Bagiya et al, , 2014Bagiya et al, , 2018Blanc & Richmond, 1980;Fejer et al, 1983;Kelley et al, 2003;Nishida, 1968;Prolss, 1997;Tsurutani et al, 2004, and references therein). Both the flare and storm induced ionospheric changes vary with the local time (e.g., Bagiya et al, 2011;Chakrabarty et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Signatures of the Solar Transient Disturbances Over the Low Latitude Ionosphere During 6 to 8 September 2017

Bagiya¹,

Thampi

Hui³

et al. 2018

JGR Space Physics

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Low latitude ionospheric behavior during solar transient disturbances of solar flares and storm time penetrating electric fields comprises an important part of the Earth's space weather. The flares enhance the electron density of the sunlit ionosphere by supplying excess solar radiation. However, the degree of these density changes is subjective if a geomagnetic storm persists simultaneously. The present case study addresses the ionospheric variations over the Indian longitudes under the combined effects of the solar flares and a geomagnetic storm during 6 to 8 September 2017 and probably the first of its kind in delineating the effects of these two over the low latitude ionosphere. The X9.3 class flare of 6 September, which occurred during non‐storm conditions, produced an intense E region ionization (~500% over the ambient). However, the total electron content response to this flare was comparatively weak. The flares on 7 and 8 September occurred during the 7–8 September geomagnetic storm. Though the 8 September flare occurred with higher intensity (M8.1) and early in local time compared to the flare of 7 September (M7.3), the equatorial electrojet current enhancement was lesser on 8 September (~75% over the ambient) than that of 7 September (~110% over the ambient). This aspect is discussed in view of the storm time convection effects over the low latitudes during 7–8 September storm. The total electron content did not respond to the flares of 7 and 8 September. This behavior is attributed to the varying center‐to‐limb distance of the solar active region 12673 during this period.

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On the Nocturnal Downward and Westward Equatorial Ionospheric Plasma Drifts During the 17 March 2015 Geomagnetic Storm

Cited by 6 publications

References 41 publications

Spatial and Temporal Confinement of the Ionospheric Responses During the St. Patrick's Day Storm of March 2015

Spatial and Temporal Confinement of the Ionospheric Responses During the St. Patrick's Day Storm of March 2015

Effects of the Relative Dynamics of Ionospheric Irregularities and GPS Satellites on Receiver Tracking Loop Performance

Signatures of the Solar Transient Disturbances Over the Low Latitude Ionosphere During 6 to 8 September 2017

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