The correlation of flare?s location on solar disc and the sudden increase of total electron content

Zhang, Donghe; Xiao, Zuo; Chang, Qing

doi:10.1360/02tb9017

Cited by 29 publications

(41 citation statements)

References 5 publications

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“…The parameters of this flare indicate that the angular distance of the flare is 85°W and is larger than the angular distances of the other two flares that occurred on 6 November 1997 and on 14 July 2000. So this result is in agreement with the conclusions made previously [ Donnelly , 1969, 1971, 1976; Matsoukas et al , 1972; Afraimovich et al , 2001c, 2002; Zhang et al , 2002b].…”

Section: Results and Analysissupporting

confidence: 94%

“…By analyzing the correlation of solar radio bursts and SITEC of the ionosphere, Matsoukas et al [1972] obtained similar results. More recently, using TEC derived from IGS network during the flares of the different X‐ray classes, Afraimovich et al [2001c, 2002] and Zhang et al [2002b] also studied the relationship between the TEC increases and the flares' parameters, and similar results were obtained. The parameters of this flare indicate that the angular distance of the flare is 85°W and is larger than the angular distances of the other two flares that occurred on 6 November 1997 and on 14 July 2000.…”

Section: Results and Analysismentioning

confidence: 67%

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Study of the ionospheric total electron content response to the great flare on 15 April 2001 using the International GPS Service network for the whole sunlit hemisphere

Zhang

Xiao

2003

J. Geophys. Res.

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[1] The characteristics of the ionospheric response to the solar flare on Apr. 15, 2001 were studied using the total electron content (TEC) obtained at GPS observational stations in the whole sunlit hemisphere under International GPS Service for Geodynamics. It was found that the largest enhancement of the sudden increase of total electron content during this flare is $2.6 TECU (1 TECU = 10 16 m À2 ). The effects of solar flare radiation on the ionosphere can be recognized even in the region at 0600 or 1800 LT. Owing to ionospheric scintillation, the TEC enhancement could not be derived from temporal TEC variation curves in high latitudes. On the other hand, the synoptic picture of the sunlit ionospheric response to the flare was obtained, and the results showed the relationship of TEC enhancements with solar zenith angles. The larger the solar zenith angle, the smaller the TEC enhancement. Even minor fast changes in TEC during this flare are revealed in the changing rate of temporal TEC variations in midlatitudes and low latitudes. These small globally synchronous disturbances of TEC were compared with the solar X-ray fluxes of this flare observed by satellites, and a close correlation between those small ionospheric disturbances and the hard X-ray flux fluctuations was found. INDEX TERMS:2435 Ionosphere: Ionospheric disturbances; 2479 Ionosphere: Solar radiation and cosmic ray effects; 7519 Solar Physics, Astrophysics, and Astronomy: Flares; 7554 Solar Physics, Astrophysics, and Astronomy: X rays, gamma rays, and neutrinos; KEYWORDS: GPS, TEC, ionosphere, flare, IGS Citation: Zhang, D. H., and Z. Xiao, Study of the ionospheric total electron content response to the great flare on 15 April 2001 using the International GPS Service network for the whole sunlit hemisphere,

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Section: Results and Analysissupporting

confidence: 94%

Section: Results and Analysismentioning

confidence: 67%

Study of the ionospheric total electron content response to the great flare on 15 April 2001 using the International GPS Service network for the whole sunlit hemisphere

Zhang

Xiao

2003

J. Geophys. Res.

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“…The time and amplitude of the peak response are determined by peak solar irradiance (e.g., Afraimovich 2000;Zhang et al 2002Zhang et al , 2011Le et al 2007). However, because of the large mass and high heat capacity in the thermosphere, the neutral gas response to a solar flare would be sluggish with regard to transient enhancement in solar EUV flux; that is, it needs longer time for neutral gas to react to the increase in solar EUV flux, and the neutral gas response also can last a longer time.…”

Section: Resultsmentioning

confidence: 99%

“…Ionospheric effects of solar flares, or sudden ionospheric disturbances (SID), have been studied since 1960s owing to their effects on radio communications and navigation systems. Most previous studies related to solar flares have so far focused on the ionospheric responses (e.g., Afraimovich 2000; Leonovich et al 2002;Liu et al 2004Liu et al , 2006Mahajan et al 2010;Tsurutani 2005;Wan et al 2005;Zhang et al 2002;Zhang and Xiao 2005;Le et al 2007Le et al , 2011Le et al , 2013Liu et al 2011). Compared to the research on the ionospheric responses to solar flares, the study on the thermospheric responses to solar flares is relatively scarce.…”

Section: Introductionmentioning

confidence: 99%

Global thermospheric disturbances induced by a solar flare: a modeling study

Ren

Liu

et al. 2015

Earth, Planets and Space

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This study focuses on the global thermosphere disturbances during a solar flare by a theoretical model of thermosphere and ionosphere. The simulated results show significant enhancements in thermospheric density and temperature in dayside hemisphere. The greatest thermospheric response occurs at the subsolar point, which shows the important effect of solar zenith angle. The results show that there are also significant enhancements in nightside hemisphere. The sudden heating due to the solar flare disturbs the global thermosphere circulation, which results in the significant change in horizontal wind. There is a significant convergence process to the antisolar point and thus the strong disturbances in the nightside occur at the antisolar point. The peak enhancements of the neutral density around antisolar point occur at about 4 h after solar flare onset. The simulated results show that thermospheric response to a solar flare mainly depends on the total integrated energy into the thermosphere, not the peak value of EUV flux. The simulated results are basically consistent with the observations derived from the CHAMP satellite, which verified the results of this modeling study.

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“…Tsurutani et al (2005) revealed that the EUV spectrum of the 28 October flare is much different from the other flares, namely in the wavelength range 260-340Å that flare is larger by more than a factor of two. The relatively weak EUV emission of the limb flare on 4 November is due to a strong center-to-limb effect for the EUV (Donnelly, 1976) and, thus, the ionospheric impact of the limb flare should also be smaller (Zhang et al, 2002b).…”

Section: Introductionmentioning

confidence: 99%

Top-side ionosphere response to extreme solar events

et al. 2006

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Abstract. Strong X-flares and solar energetic particle (SEP) fluxes are considered as sources of topside ionospheric disturbances observed by the ROCSAT-1/IPEI instrument during the Bastille Day event on 14 July 2000 and the Halloween event on 28 October-4 November 2003. It was found that within a prestorm period in the dayside ionosphere at altitudes of ∼600 km the ion density increased up to ∼80% in response to flare-associated enhancements of the solar X-ray emission. Ionospheric response to the SEP events was revealed both at sunlit and nightside hemispheres, where the ion density increased up to ∼40% and 100%, respectively. We did not find any prominent response of the ion temperature to the X-ray and SEP enhancements. The largest X-ray and SEP impacts were found for the X17 solar flare on 28 October 2003, which was characterized by the most intense fluxes of solar EUV and relativistic solar particles (Veselovsky et al., 2004). Solar events on 14 July 2000 and 29 October 2003 demonstrate weaker impacts with respect to their X-ray and SEP intensities. The weakest ionospheric response is observed for the limb X28 solar flare on 4 November 2003. The topside ionosphere response to the extreme solar events is interpreted in terms of the short-duration impact of the solar electromagnetic radiation and the long-lasting impact of the SEP.

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The correlation of flare?s location on solar disc and the sudden increase of total electron content

Cited by 29 publications

References 5 publications

Study of the ionospheric total electron content response to the great flare on 15 April 2001 using the International GPS Service network for the whole sunlit hemisphere

Study of the ionospheric total electron content response to the great flare on 15 April 2001 using the International GPS Service network for the whole sunlit hemisphere

Global thermospheric disturbances induced by a solar flare: a modeling study

Top-side ionosphere response to extreme solar events

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