A three-dimensional numerical experiment of the launching of a hot and fast coronal jet followed by several violent eruptions is analyzed in detail. These events are initiated through the emergence of a magnetic flux rope from the solar interior into a coronal hole. We explore the evolution of the emerging magnetically-dominated plasma dome surmounted by a current sheet and the ensuing pattern of reconnection. A hot and fast coronal jet with inverted-Y shape is produced that shows properties comparable to those frequently observed with EUV and X-Ray detectors. We analyze its 3D shape, its inhomogeneous internal structure, and its rise and decay phases, lasting for some 15-20 min each. Particular attention is devoted to the field-line connectivities and the reconnection pattern. We also study the cool and high-density volume that appears encircling the emerged dome. The decay of the jet is followed by a violent phase with a total of five eruptions. The first of them seems to follow the general pattern of tether-cutting reconnection in a sheared arcade, although modified by the field topology created by the preceding reconnection evolution. The two following eruptions take place near and above the strong field-concentrations at the surface. They show a twisted, Ω-loop like rope expanding in height, with twist being turned into writhe, thus hinting at a kink instability (perhaps combined with a torus-instability) as the cause of the eruption. The succession of a main jet ejection and a number of violent eruptions that resemble mini-CME's and their physical properties suggest that this experiment may provide a model for the blowout jets recently proposed in the literature.
We present stereoscopic observations of six sequent eruptions of a filament in the active region NOAA 11045 on 2010 Feb 8, with the advantage of the STEREO twin viewpoints in combination with the earth viewpoint from SOHO instruments and ground-based telescopes. The last one of the six eruptions is with a coronal mass ejection, while the others are not. The flare in this successful one is more intensive than in the others. Moreover, the filament material velocity of the successful one is also the largest among them. Interestingly, all the filament velocities are found proportional to their fla…
Context: Using unique quadrature observations with the two STEREO spacecraft, we investigate coronal dimmings at the onset of small-scale eruptions. In CMEs they are believed to indicate the opening up of the coronal magnetic fields at the start of the eruption. Aims: It is to determine whether coronal dimming seen in small-scale eruptions starts before or after chromospheric plasma ejection. Methods: One STEREO spacecraft obtained high cadence, 75 s, images in the He II 304A channel, and the other simultaneous images in the Fe IX/FeX 171A channel. We concentrate on two well-positioned chromos…
Using three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the eruption of coronal flux ropes underlying coronal streamers and the development of a prominence eruption. We initialize a quasi-steady solution of a coronal helmet streamer, into which we impose at the lower boundary the slow emergence of a part of a twisted magnetic torus. As a result a quasi-equilibrium flux rope is built up under the streamer. With varying sizes of the streamer and the different length and total twist of the emerged flux rope, we found different scenarios for the evolution from quasi-equilibri…
By using H$α$, He I 10830, EUV and soft X-ray (SXR) data, we examined a filament eruption that occurred on a quiet-sun region near the center of the solar disk on 2006 January 12, which disturbed a sigmoid overlying the filament channel observed by the $\emph{GOES-12}$ SXR Imager (SXI), and led to the eruption of the sigmoid. The event was associated with a partial halo coronal mass ejection (CME) observed by the Large Angle and Spectrometric Coronagraphs (LASCO) on board the Solar and Heliospheric Observatory ($\emph{SOHO}$), and resulted in the formation of two flare-like ribbons, post-erupt…
Successive Coronal Jets as Novel Facilitators for Filament Oscillation and Eruption
School of Physics and Astronomy, Yunnan University（云南大学物理与天文学院）；Yunnan Key Laboratory of the Solar physics and Space Science（云南省太阳物理与空间科学重点实验室）；School of Intelligence Science and Technology, Nanjing University（南京大学智能科学与技术学院）
Observations of the quiet solar corona in the 171A (~1MK) passband of the Transition Region and Coronal Explorer (TRACE) often show disruptions of the coronal part of small-scale ephemeral bipolar regions that resemble the phenomena associated with coronal mass ejections on much larger scales: ephemeral regions exhibit flare-like brightenings, rapidly rising filaments carrying absorbing material at chromospheric temperatures, or the temporary dimming of the surrounding corona. I analyze all available TRACE observing sequences between 1998/04/01 and 2009/09/30 with full-resolution 171A image se…
We study the short--term topological changes of equatorial and polar coronal hole (CH) boundaries, such as a variation of their area and disintegration, associated to reconnection with nearby (within 15$^\circ$ distance) quiescent prominence magnetic fields leading to eruptions and subsequent Coronal Mass Ejections (CMEs). The examples presented here correspond to the recent solar minimum years 2008 and 2009. We consider a temporal window of one day between the CH topological changes and the start and end times of prominence eruptions and onset of CMEs. To establish this association we took in…
We analyze the eruption of a coronal plasma channel (CPC) and an overlying flux rope using \textit{Atmospheric Imaging Assembly/Solar Dynamic Observatory} (AIA/SDO) and \textit{Solar TErrestrial RElations Observatory} (STEREO)-A spacecraft data. The CPC erupted first with its low and very faint coronal signature. Later, above the CPC, a diffuse and thin flux rope also developed and erupted. The spreading CPC further triggered a rotating jet-like structure from the coronal hole lying to its northward end. This jet-like eruption may have evolved due to the interaction between spreading CPC and t…
Most models of solar eruptions assume that coronal field lines are anchored in the dense photosphere and thus the photospheric magnetic fields would not have rapid, irreversible changes associated with eruptions resulted from the coronal magnetic reconnection. Motivated by the recent work of Hudson, Fisher & Welsch (2008) on quantitatively evaluating the back reaction due to energy release from the coronal fields, in this Letter we synthesize our previous studies and present analysis of new events about flare-related changes of photospheric magnetic fields. For the 11 X-class flares where vect…
We present observations of a failed eruption of a magnetic flux rope recorded during the M6.2 flare of 14 July 2004. The observations were mainly made with TRACE 171 Å and 1600 Å filters. The flare was accompanied by a destabilization of a magnetic structure observed as a filament eruption. After an initial acceleration the eruption slowed down and finally was stopped by the overlying coronal loops. The observations suggest that the whole event is well described by the quadrupole model of a solar flare. The failed eruption stretched the loops lying above and then they were observed oscillating…
The triggering process for coronal mass ejections (CME) in the solar atmosphere is not fully understood. We use observations from different spacecraft at several wavelengths to detect an instability process for a prominence/filament with a subsequent eruption of CME. Time series of spectral lines at 304, 171, 193, and 211 Å have been obtained with the SDO spacecraft, and at 304, 171, 195, and 284 Å with the STEREO spacecraft. A prominence/filament system was observed during November 8-23, 2011, at different angles by SDO, STEREO_A, and STEREO_B. The observations show that a giant tornado began…
We study the formation and evolution of a failed filament eruption observed in NOAA active region 11121 near the southeast limb on November 6, 2010. We use a time series of SDO/AIA 304, 171, 131, 193, 335, 94 Å images, SDO/HMI magnetograms, plus ROSA and ISOON Hαimages, to study the erupting active region. We identify coronal loop arcades associated with a quadrupolar magnetic configuration, and show that the expansion and cancelation of the central loop arcade system over the filament is followed by the eruption of the filament. The erupting filament reveals a clear helical twist and develops…
Solar eruptions are usually associated with a variety of phenomena occurring in the low corona before, during, and after onset of eruption. Though easily visible in coronagraph observations, so-called stealth coronal mass ejections (CMEs) do not obviously exhibit any of these low-coronal signatures. The presence or absence of distinct low coronal signatures can be linked to different theoretical models to establish the mechanisms by which the eruption is initiated and driven. In this study, 40 CMEs without low coronal signatures, occurring in 2012, are identified. Their observational and kinem…
Observations of the full lifetime of CBPs in data taken with the AIA on board SDO in four passbands, He II 304 A, Fe IX/X 171 A, Fe XII 193 A, and Fe XVIII 94 A are investigated for the occurrence of plasma ejections, micro-flaring, mini-filament eruptions and mini coronal mass ejections (mini-CMEs). First and foremost, our study shows that the majority (76%) of quiet Sun CBPs (31 out of 42 CBPs) produce at least one eruption during their lifetime. From 21 eruptions in 11 CBPs, 18 occur in average ~17 hrs after the CBP formation for an average lifetime of the CBPs in AIA 193 A of ~21 hrs. This…
The Sun often produces coronal mass ejections with similar structure repeatedly from the same source region, and how these homologous eruptions are initiated remains an open question. Here, by using a new magnetohydrodynamic simulation, we show that homologous solar eruptions can be efficiently produced by recurring formation and disruption of coronal current sheet as driven by continuously shearing of the same polarity inversion line within a single bipolar configuration. These eruptions are initiated by the same mechanism, in which an internal current sheet forms slowly in a gradually sheare…
Most of the commonly discussed solar coronal jets are of the type consisting of a single spire extending approximately vertically from near the solar surface into the corona. Recent research supports that eruption of a miniature filament (minifilament) drives many such single-spire jets, and concurrently generates a miniflare at the eruption site. A different type of coronal jet, identified in X-ray images during the Yohkoh era, are two-sided-loop jets, which extend from a central excitation location in opposite directions, along low-lying coronal loops more-or-less horizontal to the surface. …
Triple coronal hard X-ray source observed by STIX during a failed filament eruption
Space Research Centre, Polish Academy of Sciences（波兰科学院空间研究中心）；Astronomical Institute, University of Wrocław（弗罗茨瓦夫大学天文研究所）；ETH-Zürich（苏黎世联邦理工学院）；PMOD/WRC（帕默尔太阳物理观测站/世界辐射中心）
We investigate in detail the magnetic cause of minifilament eruptions that drive coronal-hole jets. We study 13 random on-disk coronal hole jet eruptions, using high resolution X-ray images from Hinode/XRT, EUV images from SDO/AIA, and magnetograms from SDO/HMI. For all 13 events, we track the evolution of the jet-base region and find that a minifilament of cool (transition-region-temperature) plasma is present prior to each jet eruption. HMI magnetograms show that the minifilaments reside along a magnetic neutral line between majority-polarity and minority-polarity magnetic flux patches. Thes…
Our recent observational study shows that the majority of coronal bright points (CBPs) in the quiet Sun are sources of one or more eruptions during their lifetime. Here, we investigate the non-potential time dependent structure of the magnetic field of the CBP regions with special emphasis on the time evolving magnetic structure at the spatial locations where the eruptions are initiated. The magnetic structure is evolved in time using a Non-Linear Force Free Field (NLFFF) relaxation approach, based on a time series of Helioseismic and Magnetic Imager (HMI) longitudinal magnetograms. This resul…
A highly important aspect of solar activity is the coupling between eruptions and the surrounding coronal magnetic-field topology, which determines the trajectory and morphology of the event and can even lead to sympathetic eruptions from multiple sources. In this paper, we report on a numerical simulation of a new type of coupled eruption, in which a coronal jet initiated by a large pseudostreamer filament eruption triggers a streamer-blowout coronal mass ejection (CME) from the neighboring helmet streamer. Our configuration has a large opposite-polarity region positioned between the polar co…
The coronal magnetic field evolution of 20 bipolar active regions (ARs) is simulated from their emergence to decay using the time-dependent nonlinear force-free field method of Mackay et al. A time sequence of cleaned photospheric line-of-sight magnetograms, that covers the entire evolution of each AR, is used to drive the simulation. A comparison of the simulated coronal magnetic field with the 171 and 193 A observations obtained by the Solar Dynamics Observatory (SDO)/ Atmospheric Imaging Assembly (AIA), is made for each AR by manual inspection. The results show that it is possible to reprod…
Solar X-ray jets are evidently made by a burst of reconnection of closed magnetic field in a jet's base with ambient "open" field (1,2). In the widely-accepted version of the "emerging-flux" model, that reconnection occurs at a current sheet between the open field and emerging closed field and also makes a compact hot brightening that is usually observed at the edge of the jet's base (1,3). Here we report on high-resolution X-ray and EUV observations of 20 randomly-selected X-ray jets in polar coronal holes. In each jet, contrary to the emerging-flux model, a miniature version of the filament …
Recent investigations indicate that solar coronal jets result from eruptions of small-scale chromospheric filaments, called minifilaments; that is, the jets are produced by scaled-down versions of typical-sized filament eruptions. We consider whether solar spicules might in turn be scaled-down versions of coronal jets, being driven by eruptions of "microfilaments." Assuming a microfilament's size is about a spicule's width ($\sim$300~km), the estimated occurrence number plotted against the estimated size of erupting filaments, minifilaments, and microfilaments approximately follows a power-law…
In this study, we model a sequence of a confined and a full eruption, employing the relaxed end state of the confined eruption of a kink-unstable flux rope as the initial condition for the ejective one. The full eruption, a model of a coronal mass ejection, develops as a result of converging motions imposed at the photospheric boundary, which drive flux cancellation. In this process, parts of the positive and negative external flux converge toward the polarity inversion line, reconnect, and cancel each other. Flux of the same amount as the canceled flux transfers to a flux rope, increasing the…
Coronal mass ejections (CMEs) are the most spectacular eruptive phenomena in the solar atmosphere. It is generally accepted that CMEs are results of eruptions of magnetic flux ropes (MFRs). However, a heated debate is on whether MFRs pre-exist before the eruptions or they are formed during the eruptions. Several coronal signatures, \textit{e.g.}, filaments, coronal cavities, sigmoid structures and hot channels (or hot blobs), are proposed as MFRs and observed before the eruption, which support the pre-existing MFR scenario. There is almost no reported observation about MFR formation during the…
Solar filament eruptions play a crucial role in triggering coronal mass ejections (CMEs). More than 80 % of eruptions lead to a CME. This correlation has been studied extensively during the past solar cycles and the last long solar minimum. The statistics made on events occurring during the rising phase of the new solar cycle 24 is in agreement with this finding. Both filaments and CMEs have been related to twisted magnetic fields. Therefore, nearly all the MHD CME models include a twisted flux tube, called a flux rope. Either the flux rope is present long before the eruption, or it is built u…
The phenomenon of peripheral coronal loop contraction during solar flares and eruptions, recently discovered in observations, gradually intrigues solar physicists. However, its underlying physical mechanism is still uncertain. One is Hudson (2000)'s implosion conjecture which attributes it to magnetic pressure reduction in the magnetic energy liberation core, while other researchers proposed alternative explanations. In previous observational studies we also note the disappearance of peripheral shrinking loops in the late phase, of which there is a lack of investigation and interpretation. In …
Using a 3D MHD simulation, we model the quasi-static evolution and the onset of eruption of a coronal flux rope. The simulation begins with a twisted flux rope emerging at the lower boundary and pushing into a pre-existing coronal potential arcade field. At a chosen time the emergence is stopped with the lower boundary taken to be rigid. Then the coronal flux rope settles into a quasi-static rise phase during which an underlying, central sigmoid-shaped current layer forms along the so called hyperbolic flux tube (HFT), a generalization of the X-line configuration. Reconnections in the dissipat…
We report one of several homologous non-radial eruptions from NOAA active region (AR) 11158 that are strongly modulated by the local magnetic field as observed with the Solar Dynamic Observatory (SDO). A small bipole emerged in the sunspot complex and subsequently created a quadrupolar flux system. Non-linear force-free field (NLFFF) extrapolation from vector magnetograms reveals its energetic nature: the fast-shearing bipole accumulated ~2e31 erg free energy (10% of AR total) over just one day despite its relatively small magnetic flux (5% of AR total). During the eruption, the ejected plasma…
From a magnetohydrodynamic (MHD) simulation of the eruption of a prominence hosting coronal flux rope, we carry out forward synthesis of the circular polarization signal (Stokes V signal) of the FeXIII emission line at 1074.7 nm produced by the MHD model as measured by the proposed COronal Solar Magnetism Observatory (COSMO) Large Coronagraph (LC) and infer the line-of-sight magnetic field BLOS above the limb. With an aperture of 150 cm, integration time of 12 min, and a resolution of 12 arcsec, the LC can measure a significant BLOS with sufficient signal to noise level, from the simulated flu…
We present a new methodology -- the Keplerian Optical Dynamics Analysis (KODA) -- for analyzing the dynamics of dense, cool material in the solar corona. The technique involves adaptive spatiotemporal tracking of propagating intensity gradients and their characterization in terms of time-evolving Keplerian areas swept out by the position vectors of moving plasma blobs. Whereas gravity induces purely ballistic motions consistent with Kepler's second law, non-central forces such as the Lorentz force introduce non-zero torques resulting in more complex motions. KODA algorithms enable direct evalu…
In the implosion conjecture, coronal loops contract as the result of magnetic energy release in solar eruptions and flares. However, after almost two decades, observations of this phenomenon are still rare, and most of previous reports are plagued by projection effects so that loop contraction could be either true implosion or just a change in loop inclination. In this paper, to demonstrate the reality of loop contractions in the global coronal dynamics, we present four events with the continuously contracting loops in an almost edge-on geometry from the perspective of SDO/AIA, which are free …
We present measurements of periodicity for transverse loop oscillations during the periods of activity of two remote and separated (both temporally and spatially) flares. The oscillations are observed in the same location more than 100 Mm away from the visible footpoints of the loops. Evidence for several possible excitation sources is presented. After close examination, we find that the eruptions during the flaring activities play an important role in triggering the oscillations. We investigate periodicities using time-distance, Fast Fourier Transform, and Wavelet techniques. Despite differen…
Solar flares and coronal mass ejections (CMEs) are the most powerful explosions in the Sun. They are major sources of potentially destructive space weather conditions. However, the possible causes of their initiation remain controversial. By using high resolution data observed by NST of BBSO, supplemented by Solar Dynamics Observatory (SDO) observations, we present unusual observations of a small-scale emerging flux rope near a large sunspot, whose eruption produced an M-class flare and a coronal mass ejection. The presence of the small-scale flux rope was indicated by static nonlinear force f…
We analyse multiwavelength observations of an M2.9/1N flare that occurred in AR NOAA 11112 on 16 October 2010. AIA 211 Å EUV images reveal the presence of a faster coronal wave (decelerating from ~1390 to ~830 km/s) propagating ahead of a slower wave (decelerating from ~416 to ~166 km/s) towards the western limb. The dynamic radio spectrum from Sagamore Hill radio telescope shows the presence of metric type II radio burst, which reveals the presence of a coronal shock wave (speed~800 km/s). The speed of the faster coronal wave derived from AIA 211 Å images is found to be comparable to the coro…
We present a numerical investigation of the coronal evolution of a coronal mass ejection (CME) on 2005 August 22 using a 3-D thermodynamics magnetohydrodynamic model, the SWMF. The source region of the eruption was anemone active region (AR) 10798, which emerged inside a coronal hole. We validate our modeled corona by producing synthetic extreme ultraviolet (EUV) images, which we compare to EIT images. We initiate the CME with an out-of-equilibrium flux rope with an orientation and chirality chosen in agreement with observations of a H-alpha filament. During the eruption, one footpoint of the …
Small, impulsive jets commonly occur throughout the solar corona, but are especially visible in coronal holes. Evidence is mounting that jets are part of a continuum of eruptions that extends to much larger coronal mass ejections and eruptive flares. Because coronal-hole jets originate in relatively simple magnetic structures, they offer an ideal testbed for theories of energy buildup and release in the full range of solar eruptions. We analyzed an equatorial coronal-hole jet observed by SDO/AIA on 09 January 2014, in which the magnetic-field structure was consistent with the embedded-bipole t…
Coronal disturbances associated with solar flares, such as H$α$ Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves are discussed herein in relation to magnetohydrodynamics fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a "dandelion", associated with the M1.6 flare that occurred on 2011 February 16 in the H$α$ images taken by the Flare Monitoring Telesco…
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 explosively, they began to contract at a speed of ~100 km/s, and sustained for at least 12 min, presumably due to the reduced magnetic pressure underneath with the filament escaping. Despite the contraction following the expansion, the loops of interest remained largely intact during the filament eruption, rather than formed via reconnection. These contracti…
Utilizing multiwavelength observations and magnetic field data from SDO/AIA, SDO/HMI, GOES and RHESSI, we investigate a large-scale ejective solar eruption of 2014 December 18 from active region NOAA 12241. This event produced a distinctive three-ribbon flare, having two parallel ribbons corresponding to the ribbons of a standard two-ribbon flare, and a larger-scale third quasi-circular ribbon offset from the other two ribbons. There are two components to this eruptive event. First, a flux rope forms above a strong-field polarity-inversion line and erupts and grows as the parallel ribbons turn…
We investigate the triggering mechanisms of plasma eruptions in the solar atmosphere due to interactions between emerging flux and coronal arcade fields by using two-dimensional MHD simulations. We perform parameter surveys with respect to arcade field height, magnetic field strength, and emerging flux location. Our results show that two possible mechanisms exist, and which mechanism is dominant depends mostly on emerging flux location. One mechanism appears when the location of emerging flux is close to the polarity inversion line (PIL) of an arcade field. This mechanism requires reconnection…
Solar coronal radio bursts are enhanced radio emission excited by energetic electrons accelerated during solar eruptions, studies on which are important for investigating the origin and physical mechanism of energetic particles and further diagnosing coronal parameters. Earlier studies suffered from a lack of simultaneous high-quality imaging data of the radio burst and the eruptive structure in the inner corona. Here we present a study on a complex solar radio eruption consisting of a type II and three reversely-drifting type III bursts, using simultaneous EUV and radio imaging data. It is fo…
We present both coronal and chromospheric observations of large-scale disturbances associated with a major solar eruption on 2005 September 7. In GOES/SXI, arclike coronal brightenings are recorded propagating in the southern hemisphere. The SXI front shows an initially constant speed of 730 km s$^{-1}$ and decelerates later on, and its center is near the central position angle of the associated coronal mass ejection (CME) but away from flare site. Chromospheric signatures of the disturbances are observed in both MLSO/PICS H$α$ and MLSO/CHIP He I 10830 Å, and can be divided into two parts. The…
We examine the initiation of 10 coronal jet eruptions in quiet regions on the central disk, thereby avoiding near-limb spicule-forest obscuration of the slow-rise onset of the minifilament eruption. From the SDO/AIA 171A 12-second-cadence movie of each eruption, we (1) find and compare the start times of the minifilament's slow rise, the jet-base bright point, the jet-base interior brightening, and the jet spire, and (2) measure the minifilament's speed at the start and end of its slow rise. From (a) these data, (b) prior observations showing that each eruption was triggered by magnetic flux c…
Multi-wavelength synthesis of a flux rope-trapped mini-prominence eruption and post-flare coronal rain
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；University of Helsinki（赫尔辛基大学）；Leibniz-Institut für Astrophysik Potsdam (AIP)（波茨坦莱布尼茨天体物理研究所）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Northumbria University（诺森比亚大学）
Coronal mass ejections (CMEs) play a decisive role in driving space weather, especially, the fast ones (e.g., with speeds above $800$~km~s$^{-1}$). Understanding the trigger mechanisms of fast CMEs can help us gaining important information in forecasting them. The filament eruptions accompanied with CMEs provide a good tracer in studying the early evolution of CMEs. Here we surveyed 66 filament-accompanied fast CMEs to analyse the correlation between the trigger mechanisms, namely either magnetic reconnection or ideal MHD process, associated flares, and CME speeds. Based on the data gathering …
Solar extreme ultraviolet (EUV) waves are spectacular propagating disturbances with EUV enhancements in annular shapes in the solar corona. These EUV waves carry critical information about the coronal magnetised plasma that can shed light on the elusive physical parameters (e.g. the magnetic field strength) by global solar coronal magneto-seismology. EUV waves are closely associated with a wide range of solar atmospheric eruptions, from violent flares and coronal mass ejections (CMEs) to less energetic plasma jets or mini-filament eruptions. However, the physical nature and driving mechanism o…
A single case study of a CBP in an equatorial coronal hole with an exceptionally large size is investigated to extend our understanding of the formation of mini-filaments, their destabilisation and the origin of the eruption triggering the formation of jet-like features recorded in the extreme-ultraviolet (EUV) and X-ray emission. We aim to explore the nature of the so-called micro-flares in CBPs associated with jets in coronal holes and mini coronal mass ejections in the quiet Sun. Co-observations from the Atmospheric Imaging Assembly (AIA) and Helioseismic Magnetic Imager (HMI) on board the …
We report observations of ten random on-disk solar quiet region coronal jets found in high resolution Extreme Ultraviolet (EUV) images from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and having good coverage in magnetograms from the SDO/Helioseismic and Magnetic Imager (HMI). Recent studies show that coronal jets are driven by the eruption of a small-scale filament (called a minifilament). However the trigger of these eruptions is still unknown. In the present study we address the question: what leads to the jet-driving minifilament eruptions? The EUV observations …
Stealth coronal mass ejections (CMEs) are eruptions from the Sun that have no obvious low coronal signature. These CMEs are characteristically slower events, but can still be geoeffective and affect space weather at Earth. Therefore, understanding the science underpinning these eruptions will greatly improve our ability to detect and, eventually, forecast them. We present a study of two stealth CMEs analysed using advanced image processing techniques that reveal their faint signatures in observations from the extreme ultraviolet (EUV) imagers onboard the Solar and Heliospheric Observatory (SOH…
