Abstract Magnetic reconnection is a fundamental process of topology change and energy release, taking place in plasmas on the Sun, space, astrophysical objects laboratory. However, observational evidence has been relatively rare typically only partial. Here we present fast solar filament eruption using high-resolution H-alpha images from New Vacuum Solar Telescope, supplemented by extreme ultraviolet observations. The seen to occur between set ambient chromospheric fibrils itself. This...

In this letter, we present a spectacular eruptive flare (X8.2) associated with coronal mass ejection (CME) on 2017 September 10 at the west limb of Sun. A flux rope eruption is followed by inflow, formation current sheet and cusp structure, which were simultaneously observed during occurrence flare. The hierarchical layers cusp-shaped structure are well in 131 \AA\ observation. scenario that can be created from these observations very consistent predictions some models. Except for...

To better understand the properties of solar active-region filaments, we present a detailed study on formation and magnetic structures two filaments in active region NOAA 11884 during period four days. It is found that shearing motion opposite polarities rotation small sunspots with negative polarity play an important role filaments. During these one foot was rooted sunspot polarity. The rotated not only around another polarity, but also center its umbra. By analyzing nonlinear force-free...

Magnetic reconnection is a multi-faceted process of energy conversion in astrophysical, space and laboratory plasmas that operates at microscopic scales but has macroscopic drivers consequences. Solar flares present key for its study, leaving imprints the physics radiation spectra allowing evolution to be imaged, yet full observational characterization remains elusive. Here we combine high resolution imaging spectral observations confined solar flare multiple wavelengths with...

We analyzed multi-wavelength observations of three surges with a recurrent period about 70 min in Hα, EUV, and soft X-ray, which occurred the quiet-sun region on 2000 November 3. These homologous were associated small flares at same base, but their exact footpoints spatially separated from flare. Each surge consisted cool Hα component hot, EUV or X-ray component, showed different evolutions not only space also time. The jets had slightly converging shapes, underwent more complicate...

The stability of mass transfer is important in the formation contact binaries from detached when primaries initially fill their Roche lobes. Using Eggleton's stellar evolution code, we investigate and short-period limit by considering effect instability transfer. It found that with decreasing initial primary 0.89M$_{\rm \odot}$ to 0.63M$_{\rm \odot}$, range ratio decreases for experience stable evolve into contact. If less than would dynamically unstable These systems a common envelope...

Abstract We present a clear case study on the occurrence of two successive X-class flares, including decade-class flare (X9.3) and coronal mass ejections (CMEs) triggered by shearing motion sunspot rotation in active region NOAA 12673 2017 September 6. A between main sunspots with opposite polarities began 5 lasted even after second Moreover, negative polarity rotated around its umbral center, another positive also exhibited slow rotation. The at northwest to rotate counterclockwise before...

ABSTRACT Previous studies have revealed that solar coronal jets triggered by the eruption of minifilaments (MFs) conform to famous magnetic-breakout mechanism. In such a scenario, breakout current sheet (BCS) and flare (FCS) should be observed during jets. With high spatial temporal resolution data from SDO, NVST, RHESSI, Wind, GOES, we present observational evidence BCS FCS formation driven MF occurring in active region NOAA 11726 on 2013 April 21. Magnetic field extrapolation shows was...

Abstract Tether-cutting reconnection is considered as one mechanism for the formation of a flux rope. It has been proposed more than 30 years; however, so far, direct observations it are very rare. In this Letter, we present rope via tether-cutting in NOAA AR 11967 on 2014 February 2 by combining with New Vacuum Solar Telescope and Dynamic Observatory . The occurs between two sets highly sheared magnetic arcades. Comprehensive observational evidence follows: changes connections arcades,...

We present a detailed study of the formation an inverse S-shaped filament prior to its eruption in active region NOAA 11884 from October 31 November 2, 2013. In initial stage, clockwise rotation small positive sunspot around main negative trailing formed curved filament. Then cancelled with magnetic flux create longer active-region S-shape. At cancellation site brightening was observed UV and EUV images bright material transferred Later erupted after two opposite polarities under upper part...

Solar flares and coronal mass ejections (CMEs) are the most powerful explosions in Sun. They major sources of potentially destructive space weather conditions. However, possible causes their initiation remain controversial. By using high resolution data observed by NST BBSO, supplemented Dynamics Observatory (SDO) observations, we present unusual observations a small-scale emerging flux rope near large sunspot, whose eruption produced an M-class flare ejection. The presence was indicated...

Abstract To better understand the physical connections in sympathetic solar eruptions, we investigated interaction between two nearby filaments and their successive partial eruptions active region (AR) NOAA 12866 on 2021 September 9 by using data from Solar Dynamics Observatory New Vacuum Telescope. Based H α extreme ultraviolet observations, found that right part of one filament (F1) became first experienced an obvious rolling motion. Then whole body wider expanded toward another (F2). They...

Abstract Solar filaments are spectacular objects in the solar atmosphere, consisting of accumulations cool, dense, and partially ionized plasma suspended hot corona against gravity. The magnetic structures that support filament material remain elusive, partly due to lack high-resolution field measurements chromosphere corona. In this study, we reconstruct a intermediate using EUV observations two different methods, follow injection from B-class flare. Our analysis reveals fine-scale...

Solar prominences are very spectacular structures embedded in the tenuous and hot solar corona. The counterstreaming flows, a common feature quiescent prominences, have been discovered for more than twenty years. However, mechanism driving flows is still elusive. To unveil nature of this phenomenon, we analyzed data prominence observed by New Vacuum Telescope (NVST), Interface Region Imaging Spectrograph (IRIS), Dynamical Observatory (SDO). It found that there distinct longitudinal...

Abstract Solar prominences are very spectacular structures embedded in the tenuous and hot solar corona. Counterstreaming flows, a common feature quiescent prominences, have been discovered for more than 20 yr. However, mechanism driving counterstreaming flows is still elusive. To unveil nature of this phenomenon, we analyzed data prominence observed by New Vacuum Telescope, Interface Region Imaging Spectrograph, Dynamical Observatory. It found that there distinct longitudinal oscillation...

Abstract We investigate the interaction between two filaments (F1 and F2) their subsequent magnetic reconnection in active region (AR) NOAA 13296 AR 13293 on 2023 May 9, utilizing high spatial temporal resolution multiwavelength observational data from Solar Dynamics Observatory, New Vacuum Telescope, Chinese H α Explorer. The movement of F1 southeast toward northwest, driven by motion positive polarity (P1), leads to a collision with F2. This exchanges footpoints, resulting formation new...

In order to probe the mechanism of variations Solar Constant on inter-solar-cycle scale, total solar irradiance (TSI, so-called Constant) in time interval 7 November 1978 20 September 2010 is decomposed into three components through empirical mode decomposition and time-frequency analyses. The first component rotation signal, counting up 42.31% variation TSI, which understood be mainly caused by large magnetic structures, including sunspot groups. second an annual-variation 15.17% variation,...

We present detailed analysis of an extreme-ultraviolet (EUV) wave and its interaction with active region (AR) loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly Hinode EUV Spectrometer (EIS). This was initiated from AR 11261 on 2011 August 4 propagated at velocities 430–910 km s−1. It to traverse another cross over a filament channel path. The perturbed neighboring excited disturbance that toward footpoints these loops. EIS observations revealed time transit,...

Abstract The relationship between the decay of sunspots and moving magnetic features (MMFs) plays an important role in understanding evolution active regions. We present observations two adjacent sunspots, gap them, a lot MMFs propagating from sunspots' outer edges NOAA Active Region 13023. are divided into types based on their field inclination angle: vertical (0° < γ 45°) horizontal (45° ≤ 90°) (V-MMFs H-MMFs, respectively). main results as follows: (1) mean flux rates −1.7 × 10 20 −1.4...

Abstract We report a possible current sheet region associated with small-scale magnetic reconnection event by using the spectral and imaging observations of Interface Region Imaging Spectrograph ( IRIS ) magnetograms obtained Solar Dynamics Observatory on 2016 August 08. The length width are estimated to be from 1.4 ± 0.1 Mm 3.0 0.3 0.34 0.01 0.64 0.09 Mm, respectively. evolutions positively correlated that width. These measurements among smallest reported. When slit scans region,...

Abstract Partial eruptions of solar filaments are the typical representatives eruptive behavior diversity. Here we investigate a filament partial eruption event and present integrated evidence for configuration pre-eruption its formation. The Chinese H α Solar Explorer observations reveal structured Doppler velocity distribution within filament, where distinct redshift only appeared in eastern narrow part southern region then disappeared after eruption, while northern dominated by blueshift...

"Extreme ultraviolet (EUV) waves" are large-scale wavelike transients often associated with coronal mass ejections (CMEs). In this Letter, we present a possible detection of fast-mode EUV wave mini-CME observed by the Solar Dynamics Observatory. On 2010 December 1, small-scale erupted near disk center mini-CME, which showed all low corona manifestations typical CME. The CME was triggered eruption mini-filament, length about 30''. Although tiny, had appearance an almost semicircular front and...

Abstract In order to better understand active-region filaments, we present an intensive study on the formation and eruption of a filament in active region NOAA 12241 during period from 2014 December 18 19. Using observations Helioseismic Magnetic Imager (HMI) vector magnetograms, investigate helicity injection rate, Lorentz force, vertical electric current entire associated with filament. The rate before is found be larger than that after eruption, while undergoes increase at first then...

With the observations of SDO/AIA 304 {\AA} and NVST H{\alpha} bands, we present formation process an active-region filament in active region NOAA 11903 during period from 02:00 UT to 10:00 on November 25, 2013. A series jets occurring vicinity south-western footpoint directly ejected cool hot plasma height supplied material for filament. Some newly emerging flux is found these jets. In this paper, mainly focus supply The mass uploaded by are estimated, which manifests fact that carried can...

Study on the small-scale structures and material flows of solar quiescent filaments is very important for understanding formation equilibrium filaments. Using high resolution H{\alpha} data observed by New Vacuum Solar Telescope (NVST), we present barbs along threads across spine in two 2013 September 29 2012 November 2, respectively. During evolution filament barb, several parallel tube-shaped formed width ranges from about 2.3 Mm to 3.3 Mm. The merged together accompanied with barb....