In this presentation, we report for the first time the detailed temperature evolution process of the magnetic flux rope in a failed solar eruption. Occurred on January 05, 2013, the flux rope was impulsively accelerated to a speed of ~ 400 km/s in the first minute, then decelerated and came to a complete stop in two minutes. The failed eruption resulted in a large-size high-lying (~ 100 Mm above the surface) high-temperature "fire ball" sitting in the corona for more than two hours. The time evolution of the thermal structure of the flux rope was revealed through the differential emission measure analysis technique, which produced temperature maps using observations of the Atmospheric Imaging Assembly on board Solar Dynamic Observatory. The average temperature of the flux rope steadily increased from ~ 5 MK to ~ 10 MK during the first nine minutes of the evolution, which was much longer than the rise time (about three minutes) of the associated soft X-ray flare. We suggest that the flux rope be heated by the energy release of the continuing magnetic reconnection, different from the heating of the low-lying flare loops, which is mainly produced by the chromospheric plasma evaporation. The loop arcade overlying the flux rope was pushed up by ~ 10 Mm during the attempted eruption. The pattern of the velocity variation of the loop arcade strongly suggests that the failure of the eruption be caused by the strapping effect of the overlying loop arcade.
Magnetic flux ropes are characterized by coherently twisted magnetic field lines, which are ubiquitous in magnetized plasmas. As the core structure of various eruptive phenomena in the solar atmosphere, flux ropes hold the key to understanding the physical mechanisms of solar eruptions, which impact the heliosphere and planetary atmospheres. Strongest disturbances in the Earth's space environments are often associated with large-scale flux ropes from the Sun colliding with the Earth's magnetosphere, leading to adverse, sometimes catastrophic, space-weather effects. However, it remains elusive …
We report on a study comparing coronal flux ropes inferred from eruption data with their interplanetary counterparts constructed from in situ data. The eruption data include the source-region magnetic field, post-eruption arcades, and coronal mass ejections (CMEs). Flux ropes were fit to the interplanetary CMEs (ICMEs) considered for the 2011 and 2012 Coordinated Data Analysis Workshops (CDAWs). We computed the total reconnected flux involved in each of the associated solar eruptions and found it to be closely related to flare properties, CME kinematics, and ICME properties. By fitting flux ro…
The eruptions of solar filaments often show rotational motion about their rising direction, but it remains elusive what mechanism governs such rotation and how the rotation is related to the initial morphology of the pre-eruptive filament (and co-spatial sigmoid), filament chirality, and magnetic helicity. The conventional view regarding the rotation as a result of a magnetic flux rope (MFR) under-going the ideal kink instability still has confusion in explaining these relationships. Here we proposed an alternative explanation for the rotation during eruptions, by analyzing a magnetohydrodynam…
Evolution of reconnection flux during eruption of magnetic flux ropes
Indian Institute of Astrophysics（印度天体物理研究所）；Joint Astronomy Programme and Department of Physics, Indian Institute of Science（印度科学学院天文联合项目与物理系）；University of Helsinki（赫尔辛基大学）；Amrita School of Physical Science, Amrita Vishwa Vidyapeetham（阿莫瑞塔维斯瓦维德亚佩坦姆大学阿莫瑞塔理学院）
We present a three-dimensional reconstruction of an eruption that occurred on 3 April 2010 using observations from SWAP onboard PROBA2 and SECCHI onboard STEREO. The event unfolded in two parts: an initial flow of cooler material confined to low in the corona, followed by a flux rope eruption higher in the corona. We conclude that mass off-loading from the first part triggered a rise, and, subsequently, catastrophic loss of equilibrium of the flux rope.
We analyze the formation mechanism of three homologous broad coronal mass ejections (CMEs) resulting from a series of solar blowout-eruption flares with successively increasing intensities (M2.0, M2.6, and X1.0). The flares originated from active region NOAA 12017 during 2014 March 28-29 within an interval of approximately 24 hr. Coronal magnetic field modeling based on nonlinear-force-free-field extrapolation helps to identify low-lying closed bipolar loops within the flaring region enclosing magnetic flux ropes. We obtain a double flux rope system under closed bipolar fields for the all the …
An unexpected strong geomagnetic storm occurred on 2018 August 26, which was caused by a slow coronal mass ejection (CME) from a gradual eruption of a large quiet-region filament. We investigate the eruption and propagation characteristics of this CME in relation to the strong geomagnetic storm with remote sensing and in situ observations. Coronal magnetic fields around the filament are extrapolated and compared with EUV observations. We determine the propagation direction and tilt angle of the CME flux rope near the Sun using a graduated cylindrical shell (GCS) model and the Sun-to-Earth kine…
We investigate the footpoints of four erupted magnetic flux ropes (MFRs) that appear as sigmoidal hot channels prior to the eruptions in the Atmospheric Imaging Assembly high temperaure passbands. The simultaneous Helioseismic and Magnetic Imager observations disclose that one footpoint of the MFRs originates in the penumbra or penumbra edge with a stronger magnetic field, while the other in the moss region with a weaker magnetic field. The significant deviation of the axis of the MFRs from the main polarity inversion lines and associated filaments suggests that the MFRs have ascended to a hig…
Magnetic flux ropes (MFRs) constitute the core structure of coronal mass ejections (CMEs), but hot debates remain on whether the MFR forms before or during solar eruptions. Furthermore, how flare reconnection shapes the erupting MFR is still elusive in three dimensions. Here we studied a new MHD simulation of CME initiation by tether-cutting magnetic reconnection in a single magnetic arcade. The simulation follows the whole life, including the birth and subsequent evolution, of an MFR during eruption. In the early phase, the MFR is partially separated from its ambient field by a magnetic quasi…
Solar eruptions often show the rotation of filaments, which is a manifestation of the rotation of erupting magnetic flux rope (MFR). Such a rotation of MFR can be induced by either the torque exerted by a background shear-field component (which is an external cause) or the relaxation of the magnetic twist of the MFR (an internal cause). For a given chirality of the erupting field, both the external and internal drivers cause the same rotation direction. Therefore, it remains elusive from direct observations which mechanism yields the dominant contribution to the rotation. In this paper, we exp…
Aims. We investigate the configuration of a complex flux rope above a δ sunspot region in NOAA AR 11515, and its eruptive expansion during a confined M5.3-class flare. Methods. We study the formation of the δ sunspot using continuum intensity images and photospheric vector magnetograms provided by SDO/HMI. We use EUV and UV images provided by SDO/AIA, and hard X-ray emission recorded by RHESSI to investigate the eruptive details. The coronal magnetic field is extrapolated with a non-linear force free field (NLFFF) method, based on which the flux rope is identified by calculating the twist numb…
Magnetic Reconnection Governs the Entire Lifecycle of Solar Eruptive Magnetic Flux Rope
State Key Laboratory of Solar Activity and Space Weather, School of Aerospace, Harbin Institute of Technology, Shenzhen（哈尔滨工业大学深圳航天学院）；School of Opto-electronic Engineering, Zaozhuang University（枣庄学院光电工程学院）
Solar eruptions are the main driver of space-weather disturbances at the Earth. Extreme events are of particular interest, not only because of the scientific challenges they pose, but also because of their possible societal consequences. Here we present a magnetohydrodynamic (MHD) simulation of the 14 July 2000 Bastille Day eruption, which produced a very strong geomagnetic storm. After constructing a thermodynamic MHD model of the corona and solar wind, we insert a magnetically stable flux rope along the polarity inversion line of the eruption's source region and initiate the eruption by boun…
Quasi-periodic fast-propagating (QFP) magnetosonic wave trains are commonly observed in the low corona at extreme ultraviolet wavelength bands. Here, we report the first white-light imaging observation of a QFP wave train propagating outwardly in the outer corona ranging from 2 to 4 solar Radii. The wave train was recorded by the Large Angle Spectroscopic Coronagraph on board the Solar and Heliospheric Observatory, and it was associated with a GOES M1.5 flare in NOAA active region AR12172 at the southwest limb of the solar disk. Measurements show that the speed and period of the wave train wer…
We investigate two successive flux rope (FR1 and FR2) eruptions resulting in two coronal mass ejections (CMEs) on 2012 January 23. Both FRs appeared as an EUV channel structure in the images of high temperature passbands of the Atmospheric Imaging Assembly prior to the CME eruption. Through fitting their height evolution with a function consisting of linear and exponential components, we determine the onset time of the FR impulsive acceleration with high temporal accuracy for the first time. Using this onset time, we divide the evolution of the FRs in the low corona into two phases: a slow ris…
Magnetic flux rope (MFR) is the core structure of the greatest eruptions, i.e., the coronal mass ejections (CMEs), on the Sun, and magnetic clouds are post-eruption MFRs in interplanetary space. There is a strong debate about whether or not a MFR exists prior to a CME and how the MFR forms/grows through magnetic reconnection during the eruption. Here we report a rare event, in which a magnetic cloud was observed sequentially by four spacecraft near Mercury, Venus, Earth and Mars, respectively. With the aids of a uniform-twist flux rope model and a newly developed method that can recover a shoc…
Coronal mass ejections (CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind. When these high-speed magnetized plasmas along with the energetic particles arrive at the Earth, they may interact with the magnetosphere and ionosphere, and seriously affect the safety of human high-tech activities in outer space. The travel time of a CME to 1 AU is about 1-3 days, while energetic particles from the eruptions arrive even earlier. An efficient …
