Effect of intense solar flares on TEC variation at low-latitude station Varanasi

Rao, S. S.; Rathore, Vishnu Singh; Singh, Suryabhan; Singh, Ashish Kumar

doi:10.1007/s12036-020-09637-8

Cited by 8 publications

(3 citation statements)

References 44 publications

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“…Such condition favors a strong reaction of the ionosphere to the solar flare and thus, a strong magnetic crochet in stations close to the equator. Studies of the impact of solar zenith angle on SF responses have been conducted in [7,34]. The authors of [7] focused of the sfes on ionospheric absorption with the systematic analysis of ionograms measured at mid-latitude and low-latitude ionosonde stations under different solar zenith angles.…”

Section: Discussionmentioning

confidence: 99%

A Study of Solar Flare Effects on the Geomagnetic Field Components during Solar Cycles 23 and 24

Grodji

Doumbia²,

Amaechi³

et al. 2021

Atmosphere

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In this paper, we investigated the impact of solar flares on the horizontal (H), eastward (Y) and vertical (Z) components of the geomagnetic field during solar cycles 23 and 24 (SC23/24) using data of magnetometer measurements on the sunlit side of the Earth. We examined the relation between sunspot number and solar flare occurrence of various classes during both cycles. During SC23/24, we obtained correlation coefficient of 0.93/0.97, 0.96/0.96 and 0.60/0.56 for C-class, M-class and X-class flare, respectively. The three components of the geomagnetic field reached a peak a few minutes after the solar flare occurrence. Generally, the magnetic crochet of the H component was negative between the mid-latitudes and Low-latitudes in both hemispheres and positive at low latitudes. By contrast, the analysis of the latitudinal variation of the Y and Z components showed that unlike the H component, their patterns of variations were not coherent in latitude. The peak amplitude of solar flare effect (sfe) on the various geomagnetic components depended on many factors including the local time at the observing station, the solar zenith angle, the position of the station with respect to the magnetic equator, the position of solar flare on the sun and the intensity of the flare. Thus, these peaks were stronger for the stations around the magnetic equator and very low when the geomagnetic field components were close to their nighttime values. Both cycles presented similar monthly variations with the highest sfe value (ΔHsfe = 48.82 nT for cycle 23 and ΔHsfe = 24.68 nT for cycle 24) registered in September and lowest in June for cycle 23 (ΔHsfe = 8.69 nT) and July for cycle 24 (ΔHsfe = 10.69 nT). Furthermore, the sfe was generally higher in cycle 23 than in cycle 24.

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Section: Discussionmentioning

confidence: 99%

A Study of Solar Flare Effects on the Geomagnetic Field Components during Solar Cycles 23 and 24

Grodji

Doumbia²,

Amaechi³

et al. 2021

Atmosphere

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“…This is because the sudden TEC induced by the flare is source of additional range error in critical GNSS technologies which have now found widespread usage in many endeavors. The TEC response to solar flares however depends on a number of factors including the location of the flare on the sun disk, SZA of the ionosphere, the amplitude and spectrum of the EUV and X‐ray as well as the duration of the flare (Le et al., 2013; Matsoukas et al., 1972; Singh et al., 2020) and other background information which can be longitudinal dependent (e.g., the equatorial ionization anomaly [EIA]). Results from Table 1 showed that flare induced TEC enhancements were only observed at stations located in the sunlit hemisphere.…”

Section: Discussionmentioning

confidence: 99%

Multi‐Instrument Investigation of the Impact of the Space Weather Events of 6–10 September 2017

Amaechi¹,

Akala

Oyedokun

et al. 2021

Space Weather

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Space weather refers to the variations in the Sun, solar wind, magnetosphere, ionosphere, and thermosphere, which can affect the performance of a wide range of space-borne and ground-based technological systems and pose a danger to human health and safety (Koons et al., 1999). Space weather is mainly driven by extreme solar events such as Coronal Mass Ejections (CMEs), Solar Flares (SFs) and Solar Energetic Particles (SEPs). Solar flares are large but short duration explosions on the Sun's photosphere with sudden release of large amounts of electromagnetic energy at a broad range of wavelengths, particularly in the bands of X-rays and Extreme Ultraviolet (EUV) (Tsurutani et al., 2009). CMEs are massive solar eruption of magnetized plasma structures into the interplanetary space (Tousey, 1973), while SEPs are very high-energy particles accelerated close to the Sun by rapidly varying magnetic fields and shock waves in the solar wind. The high-energy protons and electrons as well as intense radiation released during SFs can influence the state of the ionosphere hence, the propagation

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“…The propagation of radio links between satellites and the ground, which play critical roles in contemporary communications, navigation, and surveillance technologies, departs from free space circumstances in a variety of ways, with significant ramifications for the service's dependability and accuracy [15]. Over the years several studies on the behaviours of ionosphere due to solar flares, coronal mass ejections, geomagnetic storms and solar eclipses were made over different regions of ionosphere [16][17][18][19][20][21][22][23][24]. The responses of ionospheric TEC indicate both the positive and negative ionospheric effects as a result of space weather alerts such as solar flares, coronal mass ejections, and geomagnetic storms.…”

Section: Introductionmentioning

confidence: 99%

Responses of Total Electron Content to Solar Flares over Low and Mid-Latitude Regions during Sun Halo Day

Idosa,

Adhikari,

Shogile

2023

J. Nep. Phys. Soc.

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The responses of total electron content (TEC) to solar flares over low- and mid-latitude regions during the sun halo days were investigated. The research is based on GPS data obtained from Bangalore (13.02117°N, 77.57038°E) on May 24, 2021; Cape Town (-33.918861°N, 18.423300°E) on October 26, 2020; and North Dakota (46.55756°N, -96.472300°E) on December 27, 2021, during the solar halo days. The results of this study demonstrate that the values of TEC increased at Bangalore and Cape Town stations during solar halo days as compared to other days. However, over the North Dakota station, TEC during the sun halo day was greater than that on the days before and after the halo day from around 19:00 UT to 23:59 UT hours. During the sun halo over Bangalore and Cape Town stations, positive relative changes in TEC prevail, suggesting that the action of the interplanetary electric field, the prompt penetration electric field, and the disturbance dynamo electric field lead to higher TEC values. However, during the sun halo over North Dakota station, negative relative changes in TEC prevail, which might be related to the consequence that low solar activity with no earth’s field disturbances (a positive Dst) leads to lower ionospheric TEC values. Stations that have greater relative changes in TEC have shown greater power spectrum and global wave spectrum energy. Cape Town has a greater relative change in TEC, a greater power spectrum, and a larger global wave spectrum than Bangalore and North Dakota stations. The values of TEC over three stations are different due to the latitudinal and longitudinal differences in addition to the universal time effects. Finally, solar flares have a major influence on ionosphere electrodynamics, and the upward drift velocity of ionospheres at the low latitude station is more strongly influenced by solar flares due to the effects of the ExB drifts, which induce TEC disturbances during the halo days over the suggested stations.

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Effect of intense solar flares on TEC variation at low-latitude station Varanasi

Cited by 8 publications

References 44 publications

A Study of Solar Flare Effects on the Geomagnetic Field Components during Solar Cycles 23 and 24

A Study of Solar Flare Effects on the Geomagnetic Field Components during Solar Cycles 23 and 24

Multi‐Instrument Investigation of the Impact of the Space Weather Events of 6–10 September 2017

Responses of Total Electron Content to Solar Flares over Low and Mid-Latitude Regions during Sun Halo Day

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