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Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes

التفاصيل البيبلوغرافية
العنوان: Strong influence of solar X-ray flares on low-frequency electromagnetic signals in middle latitudes
المؤلفون: A. Rozhnoi, M. Solovieva, V. Fedun, P. Gallagher, J. McCauley, M. Y. Boudjada, S. Shelyag, H. U. Eichelberger
المصدر: Annales Geophysicae, Vol 37, Pp 843-850 (2019)
بيانات النشر: Copernicus Publications, 2019.
سنة النشر: 2019
المجموعة: LCC:Science
LCC:Physics
LCC:Geophysics. Cosmic physics
مصطلحات موضوعية: Science, Physics, QC1-999, Geophysics. Cosmic physics, QC801-809
الوصف: In this paper we analysed sudden phase anomalies (SPAs) of VLF–LF signals recorded at Graz (Austria), Birr (Ireland) and Moscow (Russia) stations during two strong solar flares in September 2017. The first X-class 9.3 flare occurred on 6 September at 12:02 UT, and the second X-class 8.2 flare was observed on 10 September 2017 at 16:06 UT. Data from seven transmitters in a frequency range between 20 and 45 kHz are used for the analysis. The SPAs were observed in all middle-latitude paths (differently orientated) with path lengths from 350 to 7000 km. Solar X-ray burst data were taken from GOES satellite observations in the wavelength band of 0.05–0.4 nm. It was found that (i) the amplitude of SPAs in different paths varies from 10 to 282∘, and (ii) the correlation between the amplitudes of SPAs, the lengths of paths and the signal frequency is weak. The change in effective height of reflection due to lowering of the reflecting layer during the flares was found to be about 12 km for the first event and about 9 km for the second event. Spectral analysis of the X-ray and LF data, filtered in the range between 5 s and 16 min, showed that the LF signal spectra are very similar to X-ray spectra. Maxima of both X-ray and LF spectra are in 2–16 min interval.
نوع الوثيقة: article
وصف الملف: electronic resource
اللغة: English
تدمد: 0992-7689
1432-0576
Relation: https://www.ann-geophys.net/37/843/2019/angeo-37-843-2019.pdf; https://doaj.org/toc/0992-7689; https://doaj.org/toc/1432-0576
DOI: 10.5194/angeo-37-843-2019
URL الوصول: https://doaj.org/article/b054c0f84bb14148b5b34b29baf8ff04
رقم الأكسشن: edsdoj.b054c0f84bb14148b5b34b29baf8ff04
قاعدة البيانات: Directory of Open Access Journals
الوصف
تدمد:09927689
14320576
DOI:10.5194/angeo-37-843-2019