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A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and…

Astrophysics · Physics 2008-11-26 J. Kasparova , M. Karlicky , E. P. Kontar , R. A. Schwartz , B. R. Dennis

The geomagnetic "solar flare effect" (SFE) results from excess ionization in the Earth's ionosphere, famously first detected at the time of the Carrington flare in 1859. This indirect detection of a flare constituted one of the first cases…

Solar spectra of ultraviolet bursts and flare ribbons from the Interface Region Imaging Spectrograph (IRIS) have suggested high electron densities of $>10^{12}$ cm$^{-3}$ at transition region temperatures of 0.1 MK, based on large intensity…

Solar and Stellar Astrophysics · Physics 2018-04-25 P. R. Young , F. P. Keenan , R. O. Milligan , H. Peter

Context. The Si IV lines at 1394 \r{A} and 1403 \r{A} form in the solar atmosphere at a temperature of $\sim10^{4.8}$ K. They are usually considered optically thin, but their opacity can be enhanced during solar flares. Traditionally, the…

Solar and Stellar Astrophysics · Physics 2023-07-19 Hao-Cheng Yu , J. Hong , M. D. Ding

The presence of flare related acoustic emission (sunquakes) in some flares represents a severe challenge to our current understanding of flare energy transport processes. We present a comparison of new spectral observations from Hinode's…

Solar and Stellar Astrophysics · Physics 2015-10-14 Sarah A. Matthews , Louise K. Harra , Sergei Zharkov , Lucie M. Green

The \ion{Fe}{i} lines observed by the Hinode/SOT spectropolarimeter were always seen in absorption, apart from the extreme solar limb. Here we analyse a unique dataset capturing these lines in emission during a solar white-light flare. We…

Solar and Stellar Astrophysics · Physics 2018-12-19 Jan Jurcak , Jana Kasparova , Michal Svanda , Lucia Kleint

The powerful flares that occurred in the Sun on September 4-10, 2017 are analyzed on the basis of the technique for the quantitative diagnostics of proton flares developed in IZMIRAN in 1970-1980s. It is shown that the fluxes and energy…

Solar and Stellar Astrophysics · Physics 2018-08-16 I. M. Chertok

Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated…

Solar and Stellar Astrophysics · Physics 2020-12-02 Rohit Sharma , Marina Battaglia , Yingjie Luo , Bin Chen , Sijie Yu

Solar flares involve impulsive energy release, which results in enhanced radiation over a broad spectral range and a wide range of heights. In particular, line emission from the chromosphere can provide critical diagnostics of plasma…

Solar and Stellar Astrophysics · Physics 2015-06-23 Fatima Rubio da Costa , Lucia Kleint , Vahé Petrosian , Alberto Sainz Dalda , Wei Liu

The method of measurement of Doppler frequency shift of ionospheric signal - HF Doppler technique - is one of well-known and widely used methods of ionosphere research. It allows to research various disturbances in the ionosphere. There are…

Geophysics · Physics 2014-10-15 Inna R. Petrova , Vladimir V. Bochkarev , Ruslan R. Latypov

Solar flares are known to generate seismic waves in the Sun. We present a detailed analysis of seismic emission in sunspots accompanying M- and X-class solar flares. For this purpose, we have used high-resolution Dopplergrams and…

Solar and Stellar Astrophysics · Physics 2020-07-13 Hirdesh Kumar , Brajesh Kumar

In this paper, we analyze the high-resolution UV spectra for a C1.7 solar flare (SOL2017-09-09T06:51) observed by the \textit{Interface Region Imaging Spectrograph} (\textit{IRIS}). {We focus on the spectroscopic observations at the…

Solar and Stellar Astrophysics · Physics 2020-12-02 Yi-An Zhou , Y. Li , M. D. Ding , Jie Hong , Ke Yu

Standard model of solar flares comprises a bulk expansion and rise of abruptly heated plasma (the chromospheric evaporation). Emission from plasma ascending along loops rooted on the visible solar disk should be often dominated, at least…

Solar and Stellar Astrophysics · Physics 2009-12-15 R. Falewicz , P. Rudawy , M. Siarkowski

Solar energetic particles in the heliosphere are produced by flaring processes on the Sun or shocks driven by coronal mass ejections. These particles are regularly detected remotely as electromagnetic radiation (X-rays or radio emission),…

We have compiled a catalog of solar flares as observed by the Extreme ultraviolet Imaging Telescope (EIT) aboard the Solar and Heliospheric Observatory (SOHO) spacecraft and the GOES spacecraft over a span from 1997 to 2010. During…

Solar and Stellar Astrophysics · Physics 2020-08-05 Sumanth A. Rotti , Petrus C. H. Martens , Berkay Aydin

Radio spectroscopy provides a unique inspection perspective for solar and space weather research, which can reveal the plasma and energetic electron information in the solar corona and inner heliosphere. However, Radio-Frequency…

Solar and Stellar Astrophysics · Physics 2023-02-22 Peijin Zhang , André R. Offringa , Pietro Zucca , Kamen Kozarev , Mattia Mancini

The results of a climatological study of ionospheric disturbances derived from observations of cosmic sources from the Very Large Array (VLA) Low-frequency Sky Survey (VLSS) are presented. We have used the ionospheric corrections applied to…

Space Physics · Physics 2015-06-11 J. F. Helmboldt , W. M. Lane , W. D. Cotton

Differential emission measures (DEMs) during the impulsive phase of solar flares were constructed using observations from the EUV Variability Experiment (EVE) and the Markov-Chain Monte Carlo method. Emission lines from ions formed over the…

Solar and Stellar Astrophysics · Physics 2015-06-17 Michael B. Kennedy , Ryan O. Milligan , Mihalis Mathioudakis , Francis P. Keenan

Damped Doppler shift oscillations have been observed in emission lines from ions formed at flare temperatures with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer on the Solar and Heliospheric Observatory and with the…

Astrophysics · Physics 2009-11-13 John T. Mariska , Harry P. Warren , David R. Williams , Tetsuya Watanabe