We present a rare observation of direct magnetic interaction between an activating filament and a coronal hole （CH）. The filament was a quiescent one located at the northwest of the CH. It underwent a nonradial acti...We present a rare observation of direct magnetic interaction between an activating filament and a coronal hole （CH）. The filament was a quiescent one located at the northwest of the CH. It underwent a nonradial activation, during which filament material constantly fell and intruded into the CH. As a result, the CH was clearly destroyed by the intrusion. Brightenings appeared at the boundaries and in the interior of the CH, meanwhile, its west boundaries began to retreat and the area gradually shrank. It is noted that the CH went on shrinking after the end of the intrusion and finally disappeared entirely. Following the filament activation, three coronal dimmings （D1-D3） were formed, among which D1 and D2 persisted throughout the complete disappearance of the CH. The derived coronal magnetic configuration shows that the filament was located below an extended loop system, which obviously linked D1 to D2. By extrapolating this result, our observations imply that the interaction between the filament and the CH involved direct intrusion of the filament material to the CH and the disappearance of the CH might be due to interchange reconnection between the expanding loop system and the CH＇s open field.展开更多
By using Hα, 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 ...By using Hα, 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 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 （SOHO）, and resulted in the formation of two flare-like ribbons, post-eruption coronal loops, and two transient coronal holes （TCHs）, but there were no significantly recorded GOES or Hα flares corresponding to the eruption. The two TCHs were dominated by opposite magnetic polarities and were located on the two ends of the eruptive sigmoid. They showed similar locations and shapes in He I 10830, EUV and SXR observations. During the early eruption phase, brightenings first appeared on the locations of the two subsequent TCHs, which could be clearly identified on He I 10830, EUV and SXR images. This eruption could be explained by the magnetic flux rope model, and the two TCHs were likely to be the feet of the flux rope.展开更多
Solar active region （AR） 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, whic...Solar active region （AR） 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE-MHD-NLFFF code reveals that two magnetic flux ropes （MFRs） exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface （BPSS） co- spatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament （with a length of about 200 Mm）, the eruptive MFR/filament is much smaller （with a length of about 20 Mm）, but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption.展开更多
We present observations of the eruption of a large-scale quiescent filament （LF） that is associated with the formation and eruption of a miniature filament （MF）. As a result of convergence and subsequent cancelati...We present observations of the eruption of a large-scale quiescent filament （LF） that is associated with the formation and eruption of a miniature filament （MF）. As a result of convergence and subsequent cancelation of opposite-polarity magnetic flux, MF was formed just below the spine of the LF＇s right seg- ment. Probably triggered by a nearby newly emerging flux, MF underwent a failed eruption immediately after its full development, which first ejected away from the spine of LF and then drained back to the Sun. This eruption no sooner started than the overlying LF＇s right segment began to rise slowly and the LF＇s other parts were also disturbed, and eventually the whole LF erupted bodily and quickly. These observa- tions suggest that the MF can serve as an intermediary that links the photospheric small-scale magnetic-field activities to the eruption of the overlying large filament. It appears that, rather than directly interacting with the supporting magnetic field of LF, small-scale flux cancelation and emergence in the LF＇s channel can manifest themselves as the formation and eruption of MF and so indirectly affect the stability of LE展开更多
We investigate the interaction between two filaments and the subsequent filament eruption event observed from different viewing angles by Hinode, the Solar and Heliospheric Observatory, and the Solar Terrestrial Relat...We investigate the interaction between two filaments and the subsequent filament eruption event observed from different viewing angles by Hinode, the Solar and Heliospheric Observatory, and the Solar Terrestrial Relations Observatory. In the event, the two filaments rose high, interacted with each other, and finally were ejected along two different paths. We measure the bulk-flow velocity using spectroscopic data. We find significant outflows at the speed of a few hundreds of km s 1 during the filament eruption, and also some downflows at a few tens of km s-1 at the edge of the eruption region in the late stage of the eruption. The erupting material was composed of plasmas with a wide temperature range of 10-4–106 K. These results shed light on the filament nature and the coronal dynamics.展开更多
A section of an S-shaped filament underwent an eruption in a sigmoidal active region （AR 8027） with S-shaped coronal structure, which was clearly driven by a bipole emerging below the NW end of the filament. The bip...A section of an S-shaped filament underwent an eruption in a sigmoidal active region （AR 8027） with S-shaped coronal structure, which was clearly driven by a bipole emerging below the NW end of the filament. The bipole with two separating poles showed typical characteristics of emerging flux region （EFR） and its axis rotated counterclockwise. Two canceiling magnetic features （CMFs） were formed between the two poles and adjacent flux with opposite polarity and substantial flux cancellation occurred in them. Along with the bipole emergence the filament was strongly disturbed. Just before the filament eruption, two X-ray loops overlying the filament brightened, an axial X-ray structure and then a cusp structure appeared. During the eruption first the whole filament rose and then its SE end broke away from the chromosphere, while its NW end remained stationary. Helical structure and motion were observed in the filament body and downward mass motion in the two ends. After the eruption, a major part of the filament remained and slowly returned to quiescence, and an X-ray arcade and an axial structure formed. These observations suggest that the eruption resuited from the interaction between the bipole and the overlying loops. We provide evidence that steady photospheric reconnection between their footprints took place in the two CMFs during the bipole emergence.展开更多
We report on the rare eruption of a miniature Hα filament that took the form of a surge. The filament first underwent a full development within 46 min and then began to erupt 9 min later, followed by a compact, impul...We report on the rare eruption of a miniature Hα filament that took the form of a surge. The filament first underwent a full development within 46 min and then began to erupt 9 min later, followed by a compact, impulsive X-ray class M2.2 flare with a two-ribbon nature only at the early eruption phase. During the eruption, its top rose, whereas the two legs remained rooted in the chromosphere and showed little swelling perpendicular to the rising direction. This led to a surge-like eruption with a narrow angular extent. Similar to the recent observations for standard and blowout X- ray jets by Moore et al., we thus define it as a ＂blowout Hα surge.＂ Furthermore, our observations showed that the eruption was associated with （1） a coronal mass ejection guided by a pre-existing streamer, （2） abrupt, significant, and persistent changes in the photospheric magnetic field around the filament, and （3） a sudden disappearance of a small pore. These observations thus provide evidence that a blowout surge is a small- scale version of a large-scale filament eruption in many aspects. Our observations further suggest that at least part of the Hα surges belong to blowout-type cases, and the exact distinction between the standard and blowout Hα surges is important in understanding their different origins and associated eruptive phenomena.展开更多
We present the first evidence for occurrences of magnetic interactions between a jet, a filament and coronal loops during a complex event, in which two flares sequentially occurred at different positions of the same a...We present the first evidence for occurrences of magnetic interactions between a jet, a filament and coronal loops during a complex event, in which two flares sequentially occurred at different positions of the same active region and were closely associated with two successive coronal mass ejections （CMEs）, respectively. The coronal loops were located outside but nearby the filament channel before the flares. The jet, originating from the first flare during its rise phase, not only hit the filament body but also met one of the ends of the loops. The filament then underwent an inclined eruption followed by the second flare and met the same loop end once more. Both the jet and the filament eruption were accompanied by the development of loop disturbances and the appearances of brightenings around the meeting site. In particular, the erupting filament showed clear manifestations of interactions with the loops. After a short holdup, only its portion passed through this site, while the other portion remained at the same place. Following the filament eruption and the loop disappearance, four dimmings were formed and located near their four ends. This is a situation that we define as ＂quadrupolar dimmings.＂ It appears that the two flares consisted of a sympathetic pair physically linked by the interaction between the jet and the filament, and their sympathy indicated that of the two CMEs. Moreover, it is very likely that the two sympathetic CMEs were simultaneously associated with the disappearing loops and the quadrupole dimmings.展开更多
This work investigates a typical coronal mass ejection （CME） observed on 2003 February 18, by various space and ground instruments, in white light, Ha, EUV and X- ray. The Ha and EUV images indicate that the CME sta...This work investigates a typical coronal mass ejection （CME） observed on 2003 February 18, by various space and ground instruments, in white light, Ha, EUV and X- ray. The Ha and EUV images indicate that the CME started with the eruption of a long filament located near the solar northwest limb. The white light coronal images show that the CME initiated with the rarefaction of a region above the solar limb and followed by the formation of a bright arcade at the boundary of the rarefying region at height 0.46 Re above the solar surface. The rarefying process synchronized with the slow rising phase of the eruptive filament, and the CME leading edge was observed to form as the latter started to accelerate. The lower part of the filament brightened in Ha as the filament rose to a certain height and parts of the filament was visible in the GOES X-ray images during the rise. These brightenings imply that the filament may be heated by the magnetic reconnection below the filament in the early stage of the eruption. We suggest that a possible mechanism which leads to the formation of the CME leading edge and cavity is the magnetic reconnection which takes place below the filament after the filament has reached a certain height.展开更多
We present stereoscopic observations of six sequential 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 Earth＇s viewpoint fro...We present stereoscopic observations of six sequential 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 Earth＇s viewpoint from SOHO instruments and ground-based telescopes. The last one of the six eruptions is a coronal mass ejection, but the others are not. The flare in this successful one is more intense than in the others. Moreover, the velocity of filament material in the successful one is also the largest among them. Interestingly, all the filament velocities are found to be proportional to the power of their flares. We calculate magnetic field intensity at low altitude, the decay indexes of the external field above the filament, and the asymmetry properties of the overlying fields before and after the failed eruptions and find little difference between them, indicating the same coronal confinement exists for both the failed and successful eruptions. The results suggest that, besides the confinement of the coronal magnetic field, the energy released in the low corona should be another crucial element affecting a failed or successful filament eruption. That is, a coronal mass ejection can only be launched if the energy released exceeds some critical value, given the same initial coronal conditions.展开更多
We report a filament eruption near the center of the solar disk on 1999 March 21, in multi-wavelength observations by the Yohkoh Soft X-Ray Telescope （SXT）, the Extremeultraviolet Images Telescope （EIT） and the Mi...We report a filament eruption near the center of the solar disk on 1999 March 21, in multi-wavelength observations by the Yohkoh Soft X-Ray Telescope （SXT）, the Extremeultraviolet Images Telescope （EIT） and the Michelson Doppler Imager （MDI） on the Solar and Heliospheric Observatory （SOHO）. The eruption involved in the disappearance of an Ha filament can be clearly identified in EIT 195A difference images. Two flare-like EUV ribbons and two obvious coronal dimming regions were formed. The two dimming regions had a similar appearance in lines formed in temperature range 6×10^4 K to several 10^6 K. They were located in regions of opposite magnetic polarities near the two ends of the eruptive filament. No significant X-ray or Hα flare was recorded associated with the eruption and no obvious photospheric magnetic activity was detected around the eruptive region, and particularly below the coronal dimming regions. The above surface activities were closely associated with a partial halo-type coronal mass ejection （CME） observed by the Large Angle and Spectrometric Coronagraphs （LASCO） on the SOHO. In terms of the magnetic flux rope model of CMEs, we explained these multiple observations as an integral process of largescale rearrangement of coronal magnetic field initiated by the filament eruption, in which the dimming regions marked the evacuated feet of the flux rope.展开更多
Following our previous work,we studied the partial eruption of a large-scale horse-shoe-like filament that had beenobserved in a decaying active region on the solar disk for more than 4.5 days.The filament became acti...Following our previous work,we studied the partial eruption of a large-scale horse-shoe-like filament that had beenobserved in a decaying active region on the solar disk for more than 4.5 days.The filament became active after itwas broken into two pieces,P1 and P2 seen in Hα,by magnetic reconnection between the magnetic field around itand that of a newly emerging active region nearby.P1 eventually erupted 13 hr after the breaking and escaped fromthe Sun,developing to a fast coronal mass ejection,and P2 stayed.But the mass in P1 falling down to P2 in theeruption suggests that the global magnetic fields over P1 and P2 were still connected to each other prior to theeruption.The reconnection process breaking the filament occurred outside the filament,and P1 and P2 were locatedalmost at the same altitude,so the fashion of the filament partial eruption studied here differs from that of the“double-decker model”and that of reconnection inside the filament.Analyzing the decay indices of thebackground fields above P1 and P2,n_(1)and n_(2),showed that the altitude where n_(1)exceeds the critical value of n_(c)=1.5 for the loss of equilibrium or the torus instability is lower than that where n_(2)>nc,and that n_(1)>n_(2) alwaysholds at all altitudes.Combining this fact with that the eruption occurred 13 hr after filament was broken byreconnection,we conclude that the eruption of P1 was triggered by the loss of equilibrium or the torus instability inthe configuration,and magnetic reconnection breaking the filament helped weaken the confinement of thebackground field on P1,allowing P1 to erupt.Detailed features of the eruption and the corresponding physicalscenario were also discussed.展开更多
We observed the line-of-sight magnetic field in the chromosphereand photosphere of a large quiescent filament on the solar disk on September 6, 2001 using the Solar Magnetic Field Telescope in Huairou Solar Observing ...We observed the line-of-sight magnetic field in the chromosphereand photosphere of a large quiescent filament on the solar disk on September 6, 2001 using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. The chromospheric and photospheric magnetograms together with Hβ filtergrams of the filament were examined. The filament was located on the neutral line of the large scale longitudinal magnetic field in the photosphere and the chromosphere. The lateral feet of the filament were found to be related to magnetic structures with opposite polarities. Two small lateral feet are linked to weak parasitic polarity. There is a negative magnetic structure in the photosphere under a break of the filament. At the location corresponding to the filament in the chromospheric magnetograms, the magnetic strength is found to be about 40-70 Gauss (measuring error about 39 Gauss). The magnetic signal indicates the amplitude and orientation of the internal magnetic field in the filament. We discuss several possible causes which may produce such a measured signal. A twisted magnetic configuration inside the filament is suggested .展开更多
In this paper,the well-known graduated cylindrical shell(GCS)model is slightly revised by introducing longitudinal and latitudinal deflections of prominences originating from active regions(ARs).Subsequently,it is app...In this paper,the well-known graduated cylindrical shell(GCS)model is slightly revised by introducing longitudinal and latitudinal deflections of prominences originating from active regions(ARs).Subsequently,it is applied to the three-dimensional(3D)reconstruction of an eruptive prominence in AR 13110,which produced an M1.7 class flare and a fast coronal mass ejection(CME)on 2022 September 23.It is revealed that the prominence undergoes acceleration from~246 to~708 km s^(-1).Meanwhile,the prominence experiences southward deflection by 15°±1°without longitudinal deflection,suggesting that the prominence erupts non-radially.Southward deflections of the prominence and associated CME are consistent,validating the results of fitting using the revised GCS model.Besides,the true speed of the CME is calculated to be 1637±15 km s^(-1),which is~2.3 times higher than that of prominence.This is indicative of continuing acceleration of the prominence during which flare magnetic reconnection reaches maximum beneath the erupting prominence.Hence,the reconstruction using the revised GCS model could successfully track a prominence in its early phase of evolution,including acceleration and deflection.展开更多
There are only a few observations published so far that show the initiation of a coronal mass ejection (CME) and illustrate the magnetic changes in the surface origin of a CME. Any attempt to connect a CME with its l...There are only a few observations published so far that show the initiation of a coronal mass ejection (CME) and illustrate the magnetic changes in the surface origin of a CME. Any attempt to connect a CME with its local solar activities is meaningful. In this paper we present a clear instance of a halo CME initiation. A careful analysis of magnetograms shows that the only obvious magnetic changes in the surface region of the CME is a magnetic flux cancellation underneath a quiescent filament. The early disturbance was seen as the slow upward motion in segments of the quiescent filament. Four hours later, the filament was accelerated to about 50 km s-1 and erupted. While a small part of the material in the filament was ejected into the upper corona, most of the mass was transported to a nearby region. About forty minutes later, the transported mass was also ejected partially to the upper corona. The eruption of the filament triggered a two-ribbon flare, with post-flare loops connecting the flare ribbons. A halo CME, which is inferred to be associated with the eruptive filament, was observed from LASCO/C2 and C3. The halo CME contained two CME events, each event corresponded to a partial mass ejection of the filament. We suggest that the magnetic reconnection at the lower atmosphere is responsible for the filament eruption and the halo CME.展开更多
基金Supported by the National Natural Science Foundation of China
文摘We present a rare observation of direct magnetic interaction between an activating filament and a coronal hole （CH）. The filament was a quiescent one located at the northwest of the CH. It underwent a nonradial activation, during which filament material constantly fell and intruded into the CH. As a result, the CH was clearly destroyed by the intrusion. Brightenings appeared at the boundaries and in the interior of the CH, meanwhile, its west boundaries began to retreat and the area gradually shrank. It is noted that the CH went on shrinking after the end of the intrusion and finally disappeared entirely. Following the filament activation, three coronal dimmings （D1-D3） were formed, among which D1 and D2 persisted throughout the complete disappearance of the CH. The derived coronal magnetic configuration shows that the filament was located below an extended loop system, which obviously linked D1 to D2. By extrapolating this result, our observations imply that the interaction between the filament and the CH involved direct intrusion of the filament material to the CH and the disappearance of the CH might be due to interchange reconnection between the expanding loop system and the CH＇s open field.
文摘By using Hα, 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 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 （SOHO）, and resulted in the formation of two flare-like ribbons, post-eruption coronal loops, and two transient coronal holes （TCHs）, but there were no significantly recorded GOES or Hα flares corresponding to the eruption. The two TCHs were dominated by opposite magnetic polarities and were located on the two ends of the eruptive sigmoid. They showed similar locations and shapes in He I 10830, EUV and SXR observations. During the early eruption phase, brightenings first appeared on the locations of the two subsequent TCHs, which could be clearly identified on He I 10830, EUV and SXR images. This eruption could be explained by the magnetic flux rope model, and the two TCHs were likely to be the feet of the flux rope.
基金supported by the 973 program under grant 2012CB825601the Chinese Academy of Sciences (KZZD-EW-01-4)+3 种基金the National Natural Science Foundation of China (Nos.41204126,41231068,41274192,41031066 and 41374176)the Specialized Research Fund for State Key Laboratoriessupported by NSFAGS1153323 and AGS1062050support by the Youth Innovation Promotion Association of CAS (2015122)
文摘Solar active region （AR） 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE-MHD-NLFFF code reveals that two magnetic flux ropes （MFRs） exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface （BPSS） co- spatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament （with a length of about 200 Mm）, the eruptive MFR/filament is much smaller （with a length of about 20 Mm）, but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption.
基金supported by the National Natural Science Foundation of China (NSFC,Grant Nos.11273056,11473065 and 11333007)
文摘We present observations of the eruption of a large-scale quiescent filament （LF） that is associated with the formation and eruption of a miniature filament （MF）. As a result of convergence and subsequent cancelation of opposite-polarity magnetic flux, MF was formed just below the spine of the LF＇s right seg- ment. Probably triggered by a nearby newly emerging flux, MF underwent a failed eruption immediately after its full development, which first ejected away from the spine of LF and then drained back to the Sun. This eruption no sooner started than the overlying LF＇s right segment began to rise slowly and the LF＇s other parts were also disturbed, and eventually the whole LF erupted bodily and quickly. These observa- tions suggest that the MF can serve as an intermediary that links the photospheric small-scale magnetic-field activities to the eruption of the overlying large filament. It appears that, rather than directly interacting with the supporting magnetic field of LF, small-scale flux cancelation and emergence in the LF＇s channel can manifest themselves as the formation and eruption of MF and so indirectly affect the stability of LE
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10878002 and 10933003)by the National Basic Research Program of China (973 program, Grant 2011CB811402)
文摘We investigate the interaction between two filaments and the subsequent filament eruption event observed from different viewing angles by Hinode, the Solar and Heliospheric Observatory, and the Solar Terrestrial Relations Observatory. In the event, the two filaments rose high, interacted with each other, and finally were ejected along two different paths. We measure the bulk-flow velocity using spectroscopic data. We find significant outflows at the speed of a few hundreds of km s 1 during the filament eruption, and also some downflows at a few tens of km s-1 at the edge of the eruption region in the late stage of the eruption. The erupting material was composed of plasmas with a wide temperature range of 10-4–106 K. These results shed light on the filament nature and the coronal dynamics.
基金Supported by the National Natural Science Foundation of China.
文摘A section of an S-shaped filament underwent an eruption in a sigmoidal active region （AR 8027） with S-shaped coronal structure, which was clearly driven by a bipole emerging below the NW end of the filament. The bipole with two separating poles showed typical characteristics of emerging flux region （EFR） and its axis rotated counterclockwise. Two canceiling magnetic features （CMFs） were formed between the two poles and adjacent flux with opposite polarity and substantial flux cancellation occurred in them. Along with the bipole emergence the filament was strongly disturbed. Just before the filament eruption, two X-ray loops overlying the filament brightened, an axial X-ray structure and then a cusp structure appeared. During the eruption first the whole filament rose and then its SE end broke away from the chromosphere, while its NW end remained stationary. Helical structure and motion were observed in the filament body and downward mass motion in the two ends. After the eruption, a major part of the filament remained and slowly returned to quiescence, and an X-ray arcade and an axial structure formed. These observations suggest that the eruption resuited from the interaction between the bipole and the overlying loops. We provide evidence that steady photospheric reconnection between their footprints took place in the two CMFs during the bipole emergence.
基金supported by the National Basic Research Program of China (973 program, 2011CB811400)by the National Natural Science Foundation of China (Grant Nos. 10973038 and 11173058)
文摘We report on the rare eruption of a miniature Hα filament that took the form of a surge. The filament first underwent a full development within 46 min and then began to erupt 9 min later, followed by a compact, impulsive X-ray class M2.2 flare with a two-ribbon nature only at the early eruption phase. During the eruption, its top rose, whereas the two legs remained rooted in the chromosphere and showed little swelling perpendicular to the rising direction. This led to a surge-like eruption with a narrow angular extent. Similar to the recent observations for standard and blowout X- ray jets by Moore et al., we thus define it as a ＂blowout Hα surge.＂ Furthermore, our observations showed that the eruption was associated with （1） a coronal mass ejection guided by a pre-existing streamer, （2） abrupt, significant, and persistent changes in the photospheric magnetic field around the filament, and （3） a sudden disappearance of a small pore. These observations thus provide evidence that a blowout surge is a small- scale version of a large-scale filament eruption in many aspects. Our observations further suggest that at least part of the Hα surges belong to blowout-type cases, and the exact distinction between the standard and blowout Hα surges is important in understanding their different origins and associated eruptive phenomena.
基金supported by the 973 Program (2006CB806303)the Scientific Application Foundation of Yunnan Province under grant 2007A112MNational Natural Science Foundation of China (NSFC) under grants 10573033 and 40636031.
文摘We present the first evidence for occurrences of magnetic interactions between a jet, a filament and coronal loops during a complex event, in which two flares sequentially occurred at different positions of the same active region and were closely associated with two successive coronal mass ejections （CMEs）, respectively. The coronal loops were located outside but nearby the filament channel before the flares. The jet, originating from the first flare during its rise phase, not only hit the filament body but also met one of the ends of the loops. The filament then underwent an inclined eruption followed by the second flare and met the same loop end once more. Both the jet and the filament eruption were accompanied by the development of loop disturbances and the appearances of brightenings around the meeting site. In particular, the erupting filament showed clear manifestations of interactions with the loops. After a short holdup, only its portion passed through this site, while the other portion remained at the same place. Following the filament eruption and the loop disappearance, four dimmings were formed and located near their four ends. This is a situation that we define as ＂quadrupolar dimmings.＂ It appears that the two flares consisted of a sympathetic pair physically linked by the interaction between the jet and the filament, and their sympathy indicated that of the two CMEs. Moreover, it is very likely that the two sympathetic CMEs were simultaneously associated with the disappearing loops and the quadrupole dimmings.
基金Supported by the National Natural Science Foundation of China.
文摘This work investigates a typical coronal mass ejection （CME） observed on 2003 February 18, by various space and ground instruments, in white light, Ha, EUV and X- ray. The Ha and EUV images indicate that the CME started with the eruption of a long filament located near the solar northwest limb. The white light coronal images show that the CME initiated with the rarefaction of a region above the solar limb and followed by the formation of a bright arcade at the boundary of the rarefying region at height 0.46 Re above the solar surface. The rarefying process synchronized with the slow rising phase of the eruptive filament, and the CME leading edge was observed to form as the latter started to accelerate. The lower part of the filament brightened in Ha as the filament rose to a certain height and parts of the filament was visible in the GOES X-ray images during the rise. These brightenings imply that the filament may be heated by the magnetic reconnection below the filament in the early stage of the eruption. We suggest that a possible mechanism which leads to the formation of the CME leading edge and cavity is the magnetic reconnection which takes place below the filament after the filament has reached a certain height.
基金supported by the Chinese foundations MOST (2011CB811400)the National Natural Science Foundation of China (Grant Nos. 10933003,11078004 and 11073050)
文摘We present stereoscopic observations of six sequential 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 Earth＇s viewpoint from SOHO instruments and ground-based telescopes. The last one of the six eruptions is a coronal mass ejection, but the others are not. The flare in this successful one is more intense than in the others. Moreover, the velocity of filament material in the successful one is also the largest among them. Interestingly, all the filament velocities are found to be proportional to the power of their flares. We calculate magnetic field intensity at low altitude, the decay indexes of the external field above the filament, and the asymmetry properties of the overlying fields before and after the failed eruptions and find little difference between them, indicating the same coronal confinement exists for both the failed and successful eruptions. The results suggest that, besides the confinement of the coronal magnetic field, the energy released in the low corona should be another crucial element affecting a failed or successful filament eruption. That is, a coronal mass ejection can only be launched if the energy released exceeds some critical value, given the same initial coronal conditions.
基金Supported by the National Natural Science Foundation of China.
文摘We report a filament eruption near the center of the solar disk on 1999 March 21, in multi-wavelength observations by the Yohkoh Soft X-Ray Telescope （SXT）, the Extremeultraviolet Images Telescope （EIT） and the Michelson Doppler Imager （MDI） on the Solar and Heliospheric Observatory （SOHO）. The eruption involved in the disappearance of an Ha filament can be clearly identified in EIT 195A difference images. Two flare-like EUV ribbons and two obvious coronal dimming regions were formed. The two dimming regions had a similar appearance in lines formed in temperature range 6×10^4 K to several 10^6 K. They were located in regions of opposite magnetic polarities near the two ends of the eruptive filament. No significant X-ray or Hα flare was recorded associated with the eruption and no obvious photospheric magnetic activity was detected around the eruptive region, and particularly below the coronal dimming regions. The above surface activities were closely associated with a partial halo-type coronal mass ejection （CME） observed by the Large Angle and Spectrometric Coronagraphs （LASCO） on the SOHO. In terms of the magnetic flux rope model of CMEs, we explained these multiple observations as an integral process of largescale rearrangement of coronal magnetic field initiated by the filament eruption, in which the dimming regions marked the evacuated feet of the flux rope.
基金supported by the National Key R&D Program of China No.2022YFF0503804the Strategic Priority Research Programme of the Chinese Academy of Sciences with grant XDA17040507+1 种基金the National Natural Science Foundation of China (NSFC) grant 11 933 009grants associated with the Yunling Scholar Project of Yunnan Province,the Yunnan Province Scientist Workshop of Solar Physics.
文摘Following our previous work,we studied the partial eruption of a large-scale horse-shoe-like filament that had beenobserved in a decaying active region on the solar disk for more than 4.5 days.The filament became active after itwas broken into two pieces,P1 and P2 seen in Hα,by magnetic reconnection between the magnetic field around itand that of a newly emerging active region nearby.P1 eventually erupted 13 hr after the breaking and escaped fromthe Sun,developing to a fast coronal mass ejection,and P2 stayed.But the mass in P1 falling down to P2 in theeruption suggests that the global magnetic fields over P1 and P2 were still connected to each other prior to theeruption.The reconnection process breaking the filament occurred outside the filament,and P1 and P2 were locatedalmost at the same altitude,so the fashion of the filament partial eruption studied here differs from that of the“double-decker model”and that of reconnection inside the filament.Analyzing the decay indices of thebackground fields above P1 and P2,n_(1)and n_(2),showed that the altitude where n_(1)exceeds the critical value of n_(c)=1.5 for the loss of equilibrium or the torus instability is lower than that where n_(2)>nc,and that n_(1)>n_(2) alwaysholds at all altitudes.Combining this fact with that the eruption occurred 13 hr after filament was broken byreconnection,we conclude that the eruption of P1 was triggered by the loss of equilibrium or the torus instability inthe configuration,and magnetic reconnection breaking the filament helped weaken the confinement of thebackground field on P1,allowing P1 to erupt.Detailed features of the eruption and the corresponding physicalscenario were also discussed.
基金Supported by the National Natural Science Foundation of China.
文摘We observed the line-of-sight magnetic field in the chromosphereand photosphere of a large quiescent filament on the solar disk on September 6, 2001 using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. The chromospheric and photospheric magnetograms together with Hβ filtergrams of the filament were examined. The filament was located on the neutral line of the large scale longitudinal magnetic field in the photosphere and the chromosphere. The lateral feet of the filament were found to be related to magnetic structures with opposite polarities. Two small lateral feet are linked to weak parasitic polarity. There is a negative magnetic structure in the photosphere under a break of the filament. At the location corresponding to the filament in the chromospheric magnetograms, the magnetic strength is found to be about 40-70 Gauss (measuring error about 39 Gauss). The magnetic signal indicates the amplitude and orientation of the internal magnetic field in the filament. We discuss several possible causes which may produce such a measured signal. A twisted magnetic configuration inside the filament is suggested .
基金supported by the National Key R&D Program of China 2022YFF0503003(2022YFF0503000),2021YFA1600500(2021YFA1600502)the National Natural Science Foundation of China(No.12373065)+1 种基金Yunnan Key Laboratory of Solar Physics and Space Science under the No.YNSPCC202206NSFC under grant No.12373065。
文摘In this paper,the well-known graduated cylindrical shell(GCS)model is slightly revised by introducing longitudinal and latitudinal deflections of prominences originating from active regions(ARs).Subsequently,it is applied to the three-dimensional(3D)reconstruction of an eruptive prominence in AR 13110,which produced an M1.7 class flare and a fast coronal mass ejection(CME)on 2022 September 23.It is revealed that the prominence undergoes acceleration from~246 to~708 km s^(-1).Meanwhile,the prominence experiences southward deflection by 15°±1°without longitudinal deflection,suggesting that the prominence erupts non-radially.Southward deflections of the prominence and associated CME are consistent,validating the results of fitting using the revised GCS model.Besides,the true speed of the CME is calculated to be 1637±15 km s^(-1),which is~2.3 times higher than that of prominence.This is indicative of continuing acceleration of the prominence during which flare magnetic reconnection reaches maximum beneath the erupting prominence.Hence,the reconstruction using the revised GCS model could successfully track a prominence in its early phase of evolution,including acceleration and deflection.
基金the Major Project 19791090, funded by theNational Natural Science FOundation of China (NSFC)
文摘There are only a few observations published so far that show the initiation of a coronal mass ejection (CME) and illustrate the magnetic changes in the surface origin of a CME. Any attempt to connect a CME with its local solar activities is meaningful. In this paper we present a clear instance of a halo CME initiation. A careful analysis of magnetograms shows that the only obvious magnetic changes in the surface region of the CME is a magnetic flux cancellation underneath a quiescent filament. The early disturbance was seen as the slow upward motion in segments of the quiescent filament. Four hours later, the filament was accelerated to about 50 km s-1 and erupted. While a small part of the material in the filament was ejected into the upper corona, most of the mass was transported to a nearby region. About forty minutes later, the transported mass was also ejected partially to the upper corona. The eruption of the filament triggered a two-ribbon flare, with post-flare loops connecting the flare ribbons. A halo CME, which is inferred to be associated with the eruptive filament, was observed from LASCO/C2 and C3. The halo CME contained two CME events, each event corresponded to a partial mass ejection of the filament. We suggest that the magnetic reconnection at the lower atmosphere is responsible for the filament eruption and the halo CME.
