Evidence of an Erupting Magnetic Flux Rope: LASCO Coronal Mass Ejection of 1997 April 13

1997 ◽  
Vol 490 (2) ◽  
pp. L191-L194 ◽  
Author(s):  
J. Chen ◽  
R. A. Howard ◽  
G. E. Brueckner ◽  
R. Santoro ◽  
J. Krall ◽  
...  
2015 ◽  
Vol 11 (S320) ◽  
pp. 211-217
Author(s):  
Lucie M. Green

AbstractCoronal mass ejections are the most spectacular form of solar activity and they play a key role in driving space weather at the Earth. These eruptions are associated with active regions and occur throughout an active region's entire lifetime. All coronal mass ejection models invoke the presence of a twisted magnetic field configuration known as a magnetic flux rope either before or after eruption onset. The observational identification of magnetic flux ropes in the solar atmosphere using remote sensing data represents a challenging task, but theoretical models have led to the understanding that there are signatures that reveal their presence. The range of coronal mass ejection models are helping build a more complete picture of both the trigger and drivers of these eruptions.


2021 ◽  
Vol 922 (2) ◽  
pp. 108
Author(s):  
Ju Jing ◽  
Satoshi Inoue ◽  
Jeongwoo Lee ◽  
Qin Li ◽  
Gelu M. Nita ◽  
...  

Abstract We present both the observation and the magnetohydrodynamics (MHD) simulation of the M2.4 flare (SOL2017-07-14T02:09) of NOAA active region (AR) 12665 with a goal to identify its initiation mechanism. The observation by the Atmospheric Image Assembly (AIA) on board the Solar Dynamics Observatory (SDO) shows that the major topology of the AR is a sigmoidal configuration associated with a filament/flux rope. A persistent emerging magnetic flux and the rotation of the sunspot in the core region were observed with Magnetic Imager (HMI) on board the SDO on the timescale of hours before and during the flare, which may provide free magnetic energy needed for the flare/coronal mass ejection (CME). A high-lying coronal loop is seen moving outward in AIA EUV passbands, which is immediately followed by the impulsive phase of the flare. We perform an MHD simulation using the potential magnetic field extrapolated from the measured pre-flare photospheric magnetic field as initial conditions and adopting the observed sunspot rotation and flux emergence as the driving boundary conditions. In our simulation, a sigmoidal magnetic structure and an overlying magnetic flux rope (MFR) form as a response to the imposed sunspot rotation, and the MFR rises to erupt like a CME. These simulation results in good agreement with the observation suggest that the formation of the MFR due to the sunspot rotation and the resulting torus and kink instabilities were essential to the initiation of this flare and the associated coronal mass ejection.


2020 ◽  
Author(s):  
Ute Amerstorfer ◽  
Christian Möstl ◽  
Rachel Bailey ◽  
Andreas Weiss ◽  
Martin Reiss ◽  
...  

<p>Forecasting of coronal mass ejection magnetic flux rope fields at L1 is a long-standing challenge and one of the major problems in space weather forecasting. We attempt to make progress by using two approaches: 1) machine learning approaches (e.g., linear regression, lars lasso, RANSAC, or random forest), and 2) analogue ensemble methods. For our study, we take events observed at the Wind, Stereo-A and Stereo-B satellites from the ICME list created within the EU-project HELCATS. We analyse different scores (e.g., RMSE, or the skill of the model) of the presented methods. Further, we investigate how well the flux rope field can be anticipated when the first few hours of the flux rope have already been observed at L1. </p>


2020 ◽  
Vol 6 (3) ◽  
pp. 3-17
Author(s):  
Viktor Eselevich ◽  
Maxim Eselevich

We have analyzed the fast coronal mass ejection (CME) that occurred on February 25, 2014. The analysis is based on images taken in the 131, 211, 304, and 1700 Å UV channels of the SDO/AIA instrument and from observations obtained in the Hα line (6562.8 Å) with the telescopes of the Teide and Big Bear Observatories. The February 25, 2014 CME is associated with the ejection and subsequent explosive expansion of the magnetic flux rope, which appeared near the solar surface presumably due to the tether-cutting magnetic reconnection. The impulse of full pressure (thermal plus magnetic) resulting from such an “explosion” acts on the overlying coronal arcades, causing them to merge and form an accelerated moving frontal structure of the CME. This pressure impulse also generates a blast collisional shock wave ahead of the CME, whose velocity decreases rapidly with distance. At large distances R>7R₀ (R₀ is the solar radius) from the center of the Sun in front of the CME, a shock wave of another type is formed — a “piston” collisional shock wave whose velocity varies little with distance. At R≥15R₀, there is a transition from a collisional to a collisionless shock wave.


2020 ◽  
Vol 6 (3) ◽  
pp. 3-15
Author(s):  
Viktor Eselevich ◽  
Maxim Eselevich

We have analyzed the fast coronal mass ejection (CME) that occurred on February 25, 2014. The analysis is based on images taken in the 131, 211, 304, and 1700 Å UV channels of the SDO/AIA instrument and from observations obtained in the Hα line (6562.8 Å) with the telescopes of the Teide and Big Bear Observatories. The February 25, 2014 CME is associated with the ejection and subsequent explosive expansion of the magnetic flux rope, which appeared near the solar surface presumably due to the tether-cutting magnetic reconnection. The impulse of full pressure (thermal plus magnetic) resulting from such an “explosion” acts on the overlying coronal arcades, causing them to merge and form an accelerated moving frontal structure of the CME. This pressure impulse also generates a blast collisional shock wave ahead of the CME, whose velocity decreases rapidly with distance. At large distances R>7R₀ (R₀ is the solar radius) from the center of the Sun in front of the CME, a shock wave of another type is formed — a “piston” collisional shock wave whose velocity varies little with distance. At R≥15R₀, there is a transition from a collisional to a collisionless shock wave.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Wensi Wang ◽  
Rui Liu ◽  
Yuming Wang ◽  
Qiang Hu ◽  
Chenglong Shen ◽  
...  

2006 ◽  
Vol 642 (1) ◽  
pp. 541-553 ◽  
Author(s):  
J. Krall ◽  
V. B. Yurchyshyn ◽  
S. Slinker ◽  
R. M. Skoug ◽  
J. Chen

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