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Related papers: Quasi-Periodic Pulsations in Ionospheric TEC Synch…

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Solar flare emission at X-ray and extreme ultraviolet (EUV) energies can cause substantial enhancements in the electron density in the Earth's lower ionosphere. It is now become clear that flares exhibit quasi-periodic pulsations with…

Variations in X-ray and EUV irradiance during solar flares lead to a noticeable increase in the electron concentration in the illuminated part of the Earth's ionosphere. Due to the large amount of experimental data accumulated by Global…

Earth and Planetary Astrophysics · Physics 2024-07-22 Susanna Bekker , Ryan Milligan , Ilya Ryakhovsky

We investigated the quasi-periodic pulsation (QPP) in Lyman-alpha, X-ray and extreme-ultraviolet (EUV) emissions during two solar flares, i.e., an X-class (SOL2012-01-27T) and a C-class (SOL2016-02-08T). The full-disk Lyman-alpha and X-Ray…

Solar and Stellar Astrophysics · Physics 2020-04-15 Dong Li , Lei Lu , Zongjun Ning , Li Feng , Weiqun Gan , Hui Li

A common feature of electromagnetic emission from solar flares is the presence of intensity pulsations that vary as a function of time. Known as quasi-periodic pulsations (QPPs), these variations in flux appear to include periodic…

Solar and Stellar Astrophysics · Physics 2021-04-14 Brendan P. Clarke , Laura A. Hayes , Peter T. Gallagher , Shane A. Maloney , Eoin P. Carley

Context. Extreme-ultraviolet (EUV) observations have revealed small-scale transient brightenings that may share common physical mechanisms with larger-scale solar flares. A notable feature of solar and stellar flares is the presence of…

Solar and Stellar Astrophysics · Physics 2025-05-28 Daye Lim , Tom Van Doorsselaere , David Berghmans , Laura A. Hayes , Cis Verbeeck , Nancy Narang , Marie Dominique , Andrew R. Inglis

X-ray and EUV solar flare emission cause increases in the Earth's dayside ionospheric electron density. While the response of the lower ionosphere to X-rays is well studied, the delay between EUV flare emission and the response of the…

Solar and Stellar Astrophysics · Physics 2025-08-06 Aisling N. O'Hare , Susanna Bekker , Harry J. Greatorex , Ryan O. Milligan

During a solar flare, the fluxes in various lines and continua of the solar spectrum increase, leading to enhanced ionization of the illuminated part of the Earth's ionosphere and an increase in the total electron content (TEC). It has been…

Space Physics · Physics 2025-09-01 S. Z. Bekker , R. O. Milligan , I. A. Ryakhovsky

Small scale extreme ultraviolet (EUV) transient brightenings are observationally abundant and critically important to investigate. Determining whether they share the same physical mechanisms as larger scale flares would have significant…

Solar flare emission is detected in all EM bands and variations in flux density of solar energetic particles. Often the EM radiation generated in solar and stellar flares shows a pronounced oscillatory pattern, with characteristic periods…

Solar and Stellar Astrophysics · Physics 2018-02-13 J. A. McLaughlin , V. M. Nakariakov , M. Dominique , P. Jelínek , S. Takasao

We investigate quasi-periodic pulsations (QPPs) of high-energy nonthermal emissions from an X9.3 flare (SOL2017-Sep-06T11:53), the most powerful flare since the beginning of solar cycle 24. The QPPs are identified as a series of regular and…

Solar and Stellar Astrophysics · Physics 2020-01-15 D. Li , D. Y. Kolotkov , V. M. Nakariakov , L. Lu , Z. J. Ning

Two kinds of processes could occur during the flare decay phase: processes of energy release or processes of energy relaxation. Quasi-periodic pulsations (QPPs) of the broadband emission are a good tool for the verification of mechanisms.…

Quasi-periodic fast-propagating (QFP) magnetosonic waves and extreme ultraviolet (EUV) waves were proposed to be driven by solar flares and coronal mass ejections (CMEs), respectively. In this Letter, we present a detailed analysis of an…

Solar and Stellar Astrophysics · Physics 2019-01-18 Y. H. Miao , Y. Liu , Y. D. Shen , H. B. Li , Z. Z. Abidin , A. Elmhamdi , A. S. Kordi

We report quasi-periodic pulsations (QPPs) with double periods during three solar flares (viz. SOL2011-Feb-15T01:44, SOL2011-Sep-25T04:31, SOL2012-May-17T01:25). The flare QPPs were observed from light curves in Ly$\alpha$, hard X-ray (HXR)…

Solar and Stellar Astrophysics · Physics 2021-09-08 Lei Lu , Dong Li , Zongjun Ning , Li Feng , Weiqun Gan

We report the observation of non-stationary Quasi-Periodic Pulsations (QPPs) in high-energy particles during the impulsive phase of an X4.8 flare on 2002 July 23 (SOL2002-07-23T00:35). The X4.8 flare was simultaneously measured by the…

Solar and Stellar Astrophysics · Physics 2022-06-08 Dong Li , Wei Chen

Quasi-periodic pulsations (QPPs), which usually appear as temporal pulsations of the total flux, are frequently detected in the light curves of solar/stellar flares. In this study, we present the investigation of non-stationary QPPs with…

Solar and Stellar Astrophysics · Physics 2021-11-24 Dong Li , Mingyu Ge , Marie Dominique , Haisheng Zhao , Gang Li , Xiaobo Li , Shuangnan Zhang , Fangjun Lu , Weiqun Gan , Zongjun Ning

Studies in the extreme ultraviolet (EUV) and X-ray ranges of the solar spectrum are important due to the active role of radiation of these ranges in the formation of the Earth's ionosphere. Photons of the EUV range are completely absorbed…

Solar and Stellar Astrophysics · Physics 2019-12-24 E. A. Bruevich , G. V. Yakunina

Solar flares often display pulsating and oscillatory signatures in the emission, known as quasi-periodic pulsations (QPP). QPP are typically identified during the impulsive phase of flares, yet in some cases, their presence is detected late…

Solar and Stellar Astrophysics · Physics 2019-04-17 Laura A. Hayes , Peter T. Gallagher , Brian R. Dennis , Jack Ireland , Andrew Inglis , Diana E. Morosan

The solar irradiance in the Extreme Ultraviolet (EUV) spectral bands has been observed with a 15 sec cadence by the SOHO Solar EUV Monitor (SEM) since 1995. During remarkably intense solar flares the SEM EUV measurements are saturated in…

Astrophysics · Physics 2009-11-11 L. V. Didkovsky , D. L. Judge , A. R. Jones , S. Wieman , B. T. Tsurutani , D. McMullin

We report multi-wavelength observations of four solar flares on 2014 July 07. We firstly select these flares according to the soft X-ray (SXR) and extreme ultraviolet (EUV) emissions recorded by the Extreme Ultraviolet Variability…

Solar and Stellar Astrophysics · Physics 2021-05-05 Dong Li , Alexander Warmuth , Lei Lu , Zongjun Ning

We report a quasi-periodic pulsation (QPP) event simultaneously detected from the spatial displacements of coronal loop at both EUV images and microwave emission during the preflare phase of a C1.1 flare on 2016 March 23. Using the motion…

Solar and Stellar Astrophysics · Physics 2020-04-22 Dong Li , Ying Li , Lei Lu , Qingmin Zhang , Zongjun Ning , Sergey Anfinogentov
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