Related papers: Observational Evidence for Coronal Twisted Flux Ro…
Multi-instrument observations of NOAA AR10938 on Jan. 14-18, 2007, are utilized to study the evolution of a magnetic thread system with multiple crossings suggestive of a twisted coronal flux rope. A C-class flare recorded by GOES on Jan.…
We analyse the relationship between two near filaments, which do not show any connection in H-alpha images but reveal close magnetic connectivity during filament activations in Extreme Ultraviolet (EUV) observations. A twisted flux rope,…
We present the Solar Dynamics Observatory observations of two flux ropes respectively tracked out by material from a surge and a failed filament eruption on 2012 July 29 and August 04. For the first event, the interaction between the…
Previous studies have found that coronal loops have a nearly uniform thickness, which seems to disagree with the characteristic expansion of active region magnetic fields. This is one of the most intriguing enigmas in solar physics. We here…
Using high-resolution observations from the 1.6 m New Solar Telescope (NST) operating at the Big Bear Solar Observatory (BBSO), we report direct evidence of merging/reconnection of cool H$\alpha$ loops in the chromosphere during two…
Formed through magnetic field shearing and reconnection in the solar corona, magnetic flux ropes are structures of twisted magnetic field, threaded along an axis. Their evolution and potential eruption are of great importance for space…
We analyse multiwavelength observations of a western limb flare (C3.9) occurred in AR NOAA 111465 on 30 April 2012. The high resolution images recorded by SDO/AIA 304, 1600 \AA\ and Hinode/SOT H$\alpha$ show the activation of a…
We present multispectral analysis (radio, H$\alpha$, UV/EUV, and hard X-ray) of a confined flare from 2015 March 12. This flare started within the active region NOAA 12 297 and then it expanded into a large preexisting magnetic rope…
We studied the magnetic topology of active region 12158 on 2014 September 10 and compared it with the observations before and early in the flare which begins at 17:21 UT (SOL2014-09-10T17:45:00). Our results show that the sigmoidal…
We analyze the imaging observations of an M-class eruptive flare of 2015 November, 4. The pre-eruptive H alpha filament was modelled by the non-linear force free field model, which showed that it consisted of two helical systems.…
We analyse imaging (EUV, X-ray) and spectral (radio, X-ray) data obtained by ground based and space instruments on board space missions both on Earth (Fermi, Hinode, Solar Dynamics Observatory) and solar orbit (Solar Orbiter, STEREO-A),…
In this study we report detailed observations of magnetic environment at four footpoints of two warm coronal loops observed on 5 May 2016 in NOAA AR 12542 (Loop I) and 17 Dec 2015 in NOAA AR 12470 (Loop II). These loops were connecting a…
Multi-wavelength observations of a sigmoidal (S-shaped) solar coronal source by the EUV Imaging Spectrometer and the X-ray Telescope aboard the Hinode spacecraft and by the EUV Imager aboard STEREO are reported. The data reveal the…
We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties…
We study the magnetic field structures of hard X-ray sources and flare ribbons of the M1.1 flare in active region NOAA 10767 on 2005 May 27. We have found in a nonlinear force-free field extrapolation, over the same polarity inversion line,…
Magnetic flux rope is believed to be an important structural component of coronal mass ejections (CMEs). While there exist much observational evidence of the flux rope after the eruption, e.g., as seen in remote-sensing coronagraph images…
Solar active region 11283 produced an X2.1 flare associated with a solar eruption on September 6, 2011. Observations revealed a preflare sigmoidal structure and a circular flare ribbon surrounding the typical two ribbon structure, along…
We study the evolution of a group of TRACE 195 A coronal loops overlying a reverse S-shaped filament on 2001 June 15. These loops were initially pushed upward with the filament ascending and kinking slowly, but as soon as the filament rose…
The magnetic flux rope (MFR) is believed to be the underlying magnetic structure of coronal mass ejections (CMEs). However, it remains unclear how an MFR evolves into and forms the multi-component structure of a CME. In this paper, we…
We report on observations of conversion of bright filament strands into flare loops during 2012 August 31 filament eruption. Prior to the eruption, individual bright strands composing one of the legs of the filament were observed in the 171…