English
Related papers

Related papers: Systematic non-thermal velocity increase preceding…

200 papers

The velocity pattern of a fan loop structure within a solar active region over the temperature range 0.15-1.5 MK is derived using data from the EUV Imaging Spectrometer (EIS) on board the Hinode satellite. The loop is aligned towards the…

Solar and Stellar Astrophysics · Physics 2015-05-28 P. R. Young , B. O'Dwyer , H. E. Mason

Magnetohydrodynamic (MHD) plasma turbulence is believed to play a vital role in the production of energetic electrons during solar flares and the non-thermal broadening of spectral lines is a key sign of this turbulence. Here, we determine…

Solar and Stellar Astrophysics · Physics 2021-12-22 Morgan Stores , Natasha L. S. Jeffrey , Eduard P. Kontar

With machine learning entering into the awareness of the heliophysics community, solar flare prediction has become a topic of increased interest. Although machine learning models have advanced with each successive publication, the input…

Solar and Stellar Astrophysics · Physics 2020-03-11 Brandon Panos , Lucia Kleint

Large solar flares (GOES M-class or higher) are usually associated with eruptions of material. However, when considering flare irradiance enhancements and dynamics such as chromospheric evaporation, potential contributions from erupted…

Solar and Stellar Astrophysics · Physics 2025-12-18 Luke Majury , Marie Dominique , Ryan Milligan , Dana-Camelia Talpeanu , Ingolf Dammasch , David Berghmans

Solar filaments exist as stable structures for extended periods of time before many of them form the core of a CME. We examine the properties of an erupting filament on 2017 May 29--30 with high-resolution He I 10830 A and Halpha spectra…

We report the observation of an unusual cold, tenuous solar flare, which reveals itself via numerous and prominent non-thermal manifestations, while lacking any noticeable thermal emission signature. RHESSI hard X-rays and 0.1-18 GHz radio…

Solar and Stellar Astrophysics · Physics 2015-05-27 Gregory D. Fleishman , Eduard P. Kontar , Gelu M. Nita , Dale E. Gary

In this article, we measure the mean magnetic shear from the morphological evolution of flare ribbons, and examine the evolution of flare thermal and non-thermal X-ray emissions during the progress of flare reconnection. We analyze three…

Solar and Stellar Astrophysics · Physics 2022-07-20 Jiong Qiu , Jianxia Cheng

Identifying the source of the material within coronal mass ejections (CMEs) and understanding CME onset mechanisms are fundamental issues in solar and space physics. Parameters relating to plasma composition, such as charge states and He…

Solar and Stellar Astrophysics · Physics 2020-09-09 Hui Fu , R. A. Harrison , J. A. Davies , LiDong Xia , XiaoShuai Zhu , Bo Li , ZhengHua Huang , D. Barnes

We present the first observational study of the onset and evolution of solar flare turbulence in the lower solar atmosphere on an unprecedented time scale of 1.7 s using the Interface Region Imaging Spectrograph observing plasma at a…

Solar and Stellar Astrophysics · Physics 2018-12-27 N. L. S. Jeffrey , L. Fletcher , N. Labrosse , P. J. A. Simões

Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare observed on 2011 February 16 07:44…

Solar and Stellar Astrophysics · Physics 2015-06-12 Peter Young , George Doschek , Harry Warren , Hiro Hara

From Doppler velocity maps of active regions constructed from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km/s) that can persist for at least a…

Astrophysics · Physics 2009-11-13 G. A. Doschek , H. P. Warren , J. T. Mariska , K. Muglach , J. L. Culhane , H. Hara , T Watanabe

A M-class behind-the-limb solar flare on 1 May 2013 (SOL2013-05-01T02:32), accompanied by a ($\sim$ 400 km/s) CME was observed by several space-based observatories with different viewing angles. We investigated the RHESSI-observed occulted…

We investigate the influence of the variations of energy spectrum of non-thermal electrons on the resulting GOES classes of solar flares. Twelve observed flares with various soft to hard X-ray emission ratios were modelled using different…

Solar and Stellar Astrophysics · Physics 2009-09-25 R. Falewicz , P. Rudawy , M. Siarkowski

Solar flares are observed and classified according to their intensity measured with the GOES X-ray Sensors. We show that the duration of a flare, as measured by the full width at half maximum (FWHM) in GOES is not related to the size of the…

Solar and Stellar Astrophysics · Physics 2019-04-10 Jeffrey W. Reep , Kalman J. Knizhnik

Using the potential of two unprecedented missions, STEREO and RHESSI, we study three well observed fast CMEs that occurred close to the limb together with their associated high energy flare emissions in terms of RHESSI HXR spectra and flux…

Solar and Stellar Astrophysics · Physics 2015-05-18 M. Temmer , A. M. Veronig , E. P. Kontar , S. Krucker , B. Vrsnak

In this study we compared the temporal and periodic variations of the Maximum CME Speed Index (MCMESI) and the number of different class (C, M, and X) solar X-Ray flares for the last two solar cycles (Cycle 23 and 24). To obtain the…

Solar and Stellar Astrophysics · Physics 2020-11-25 A. Kilcik , P. Chowdhury , V. Sarp , V. Yurchyshyn , B. Donmez , J. P. Rozelot , A. Ozguc

In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared to the predictions of an analytical 0-D hydrodynamic…

Solar and Stellar Astrophysics · Physics 2014-01-17 Daniel F. Ryan , Phillip C. Chamberlin , Ryan O. Milligan , Peter T. Gallgher

An X1.6 flare occurred in AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode, IRIS, SDO, and RHESSI. We analyze a bright kernel which produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak.…

Solar and Stellar Astrophysics · Physics 2017-02-22 Kyoung-Sun Lee , Shinsuke Imada , Kyoko Watanabe , Yumi Bamba , David H. Brooks

We analyse the temporal evolution of the Differential Emission Measure (DEM) of solar active regions and explore its usage in solar flare prediction. The DEM maps are provided by the Gaussian Atmospheric Imaging Assembly (GAIA-DEM) archive,…

Solar and Stellar Astrophysics · Physics 2020-11-13 C. Gontikakis , I. Kontogiannis , M. K. Georgoulis , C. Guennou , P. Syntelis , S. H. Park , E. Buchlin

In this study, we investigate motions in the hot plasma above the flare loops during the 2017 September 10 X8.2 flare event. We examine the region to the south of the main flare arcade, where there is data from the Interface Region Imaging…

Solar and Stellar Astrophysics · Physics 2021-01-06 Katharine K. Reeves , Vanessa Polito , Bin Chen , Giselle Galan , Sijie Yu , Wei Liu , Gang Li