Responses of the D region ionosphere to solar flares revealed by MF radar measurements

Na Li; Jiuhou Lei; Xiaoli Luan; Jinsong Chen; Jiahao Zhong; Qian Wu; Zhengwen Xu; Leke Lin

doi:10.1016/j.jastp.2018.11.014

Responses of the D region ionosphere to solar flares revealed by MF radar measurements

Na Li, Jiuhou Lei, Xiaoli Luan, Jinsong Chen, Jiahao Zhong, Qian Wu, Zhengwen Xu, Leke Lin

Geospace Frontiers

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12 Scopus citations

Abstract

Electron density (N_e) and effective reflection height (H^’, where the electron density reaches its peak value) in the D region observed by medium frequency (MF) radar at Kunming (25.6°N, 103.8°E) were utilized to quantitatively study the ionospheric response to solar flares. It was found that the H^’ and N_e had profound responses to solar flares. The results showed a sharp decrease in the H^’ from 76 to 80 km during the non-flare period to nearly 58 km with flares, and a sudden increase in the N_e from below 4×10⁸ m³ in non-flare period to 1.8×10⁹ m³ during 13 M-level flares. The behavior of N_e was strongly and positively correlated with the variation of the X-ray flux, with the largest coefficient being 0.93, while the changes of H^’ exhibited a strongly negative correlation of −0.96 with that of the X-ray flux. Moreover, variations of H^’ and ΔN_e depended on not only the flare level, but also upon the onset time and duration of flare.

Original language	English
Pages (from-to)	211-216
Number of pages	6
Journal	Journal of Atmospheric and Solar-Terrestrial Physics
Volume	182
DOIs	https://doi.org/10.1016/j.jastp.2018.11.014
State	Published - Jan 2019

Keywords

Electron density
MF radar
Reflection height
Solar flare

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10.1016/j.jastp.2018.11.014

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@article{f7ed9db7ba1f4779acea0c0e39152dc7,

title = "Responses of the D region ionosphere to solar flares revealed by MF radar measurements",

abstract = "Electron density (Ne) and effective reflection height (H{\textquoteright}, where the electron density reaches its peak value) in the D region observed by medium frequency (MF) radar at Kunming (25.6°N, 103.8°E) were utilized to quantitatively study the ionospheric response to solar flares. It was found that the H{\textquoteright} and Ne had profound responses to solar flares. The results showed a sharp decrease in the H{\textquoteright} from 76 to 80 km during the non-flare period to nearly 58 km with flares, and a sudden increase in the Ne from below 4×108 m3 in non-flare period to 1.8×109 m3 during 13 M-level flares. The behavior of Ne was strongly and positively correlated with the variation of the X-ray flux, with the largest coefficient being 0.93, while the changes of H{\textquoteright} exhibited a strongly negative correlation of −0.96 with that of the X-ray flux. Moreover, variations of H{\textquoteright} and ΔNe depended on not only the flare level, but also upon the onset time and duration of flare.",

keywords = "Electron density, MF radar, Reflection height, Solar flare",

author = "Na Li and Jiuhou Lei and Xiaoli Luan and Jinsong Chen and Jiahao Zhong and Qian Wu and Zhengwen Xu and Leke Lin",

note = "Publisher Copyright: {\textcopyright} 2018",

year = "2019",

month = jan,

doi = "10.1016/j.jastp.2018.11.014",

language = "English",

volume = "182",

pages = "211--216",

journal = "Journal of Atmospheric and Solar-Terrestrial Physics",

issn = "1364-6826",

publisher = "Elsevier Ltd",

}

TY - JOUR

T1 - Responses of the D region ionosphere to solar flares revealed by MF radar measurements

AU - Li, Na

AU - Lei, Jiuhou

AU - Luan, Xiaoli

AU - Chen, Jinsong

AU - Zhong, Jiahao

AU - Wu, Qian

AU - Xu, Zhengwen

AU - Lin, Leke

PY - 2019/1

Y1 - 2019/1

N2 - Electron density (Ne) and effective reflection height (H’, where the electron density reaches its peak value) in the D region observed by medium frequency (MF) radar at Kunming (25.6°N, 103.8°E) were utilized to quantitatively study the ionospheric response to solar flares. It was found that the H’ and Ne had profound responses to solar flares. The results showed a sharp decrease in the H’ from 76 to 80 km during the non-flare period to nearly 58 km with flares, and a sudden increase in the Ne from below 4×108 m3 in non-flare period to 1.8×109 m3 during 13 M-level flares. The behavior of Ne was strongly and positively correlated with the variation of the X-ray flux, with the largest coefficient being 0.93, while the changes of H’ exhibited a strongly negative correlation of −0.96 with that of the X-ray flux. Moreover, variations of H’ and ΔNe depended on not only the flare level, but also upon the onset time and duration of flare.

AB - Electron density (Ne) and effective reflection height (H’, where the electron density reaches its peak value) in the D region observed by medium frequency (MF) radar at Kunming (25.6°N, 103.8°E) were utilized to quantitatively study the ionospheric response to solar flares. It was found that the H’ and Ne had profound responses to solar flares. The results showed a sharp decrease in the H’ from 76 to 80 km during the non-flare period to nearly 58 km with flares, and a sudden increase in the Ne from below 4×108 m3 in non-flare period to 1.8×109 m3 during 13 M-level flares. The behavior of Ne was strongly and positively correlated with the variation of the X-ray flux, with the largest coefficient being 0.93, while the changes of H’ exhibited a strongly negative correlation of −0.96 with that of the X-ray flux. Moreover, variations of H’ and ΔNe depended on not only the flare level, but also upon the onset time and duration of flare.

KW - Electron density

KW - MF radar

KW - Reflection height

KW - Solar flare

UR - https://www.scopus.com/pages/publications/85058046813

U2 - 10.1016/j.jastp.2018.11.014

DO - 10.1016/j.jastp.2018.11.014

M3 - Article

AN - SCOPUS:85058046813

SN - 1364-6826

VL - 182

SP - 211

EP - 216

JO - Journal of Atmospheric and Solar-Terrestrial Physics

JF - Journal of Atmospheric and Solar-Terrestrial Physics

ER -

Responses of the D region ionosphere to solar flares revealed by MF radar measurements

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Keywords

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