scholarly journals Understanding the Initiation of the M2.4 Flare on 2017 July 14

2021 ◽  
Vol 922 (2) ◽  
pp. 108
Author(s):  
Ju Jing ◽  
Satoshi Inoue ◽  
Jeongwoo Lee ◽  
Qin Li ◽  
Gelu M. Nita ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Coronal Mass Ejection ◽  
Initial Conditions ◽  
Magnetic Energy ◽  
Flux Rope ◽  
Solar Dynamics Observatory ◽  
Initiation Mechanism ◽  
Mhd Simulation ◽  
Mass Ejection

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.

scholarly journals Photospheric magnetic field of an eroded-by-solar-wind coronal mass ejection

2016 ◽  
Vol 12 (S327) ◽  
pp. 67-70
Author(s):  
J. Palacios ◽  
C. Cid ◽  
E. Saiz ◽  
A. Guerrero
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Coronal Mass Ejection ◽  
Coronal Hole ◽  
Interplanetary Medium ◽  
Flux Rope ◽  
Magnetic Characteristics ◽  
Interplanetary Coronal Mass Ejection ◽  
Fast Wind ◽  
Mass Ejection

AbstractWe have investigated the case of a coronal mass ejection that was eroded by the fast wind of a coronal hole in the interplanetary medium. When a solar ejection takes place close to a coronal hole, the flux rope magnetic topology of the coronal mass ejection (CME) may become misshapen at 1 AU as a result of the interaction. Detailed analysis of this event reveals erosion of the interplanetary coronal mass ejection (ICME) magnetic field. In this communication, we study the photospheric magnetic roots of the coronal hole and the coronal mass ejection area with HMI/SDO magnetograms to define their magnetic characteristics.

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 ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Coronal Mass Ejection ◽  
Flux Rope ◽  
Magnetic Flux Rope ◽  
Mass Ejection

scholarly journals The CME link to geomagnetic storms

2009 ◽  
Vol 5 (S264) ◽  
pp. 326-335 ◽  
Author(s):  
Nat Gopalswamy
Keyword(s):  
Magnetic Field ◽  
Free Energy ◽  
Coronal Mass Ejection ◽  
High Speed ◽  
Geomagnetic Storms ◽  
Flux Rope ◽  
Active Regions ◽  
Angular Width ◽  
Central Meridian ◽  
Mass Ejection

AbstractThe coronal mass ejection (CME) link to geomagnetic storms stems from the southward component of the interplanetary magnetic field contained in the CME flux ropes and in the sheath between the flux rope and the CME-driven shock. A typical storm-causing CME is characterized by (i) high speed, (ii) large angular width (mostly halos and partial halos), and (iii) solar source location close to the central meridian. For CMEs originating at larger central meridian distances, the storms are mainly caused by the sheath field. Both the magnetic and energy contents of the storm-producing CMEs can be traced to the magnetic structure of active regions and the free energy stored in them.

scholarly journals Mass ejections from the Sun

2015 ◽  
Vol 11 (S320) ◽  
pp. 211-217
Author(s):  
Lucie M. Green
Keyword(s):  
Magnetic Flux ◽  
Coronal Mass Ejection ◽  
Flux Rope ◽  
Remote Sensing Data ◽  
Active Regions ◽  
Theoretical Models ◽  
Field Configuration ◽  
Magnetic Flux Rope ◽  
Magnetic Flux Ropes ◽  
Mass Ejection

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.

Effects of optimisation parameters on data-driven magnetofrictional modelling 

2021 ◽  
Author(s):  
Anshu Kumari ◽  
Daniel Price ◽  
Emilia Kilpua ◽  
Jens Pomoell ◽  
Farhad Daei
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Large Scale ◽  
Magnetic Energy ◽  
Flux Rope ◽  
Coronal Magnetic Field ◽  
Early Evolution ◽  
Data Driven ◽  
Magnetic Field Magnitude ◽  
Mass Ejection

<p>The solar coronal magnetic field plays an important role in the formation, evolution, and dynamics of small and large-scale structures in the corona. Estimation of the coronal magnetic field, the ultimate driver of space weather, particularly in the ‘low’ and ‘middle’ corona, is presently limited due to practical difficulties. Data-driven time-dependent magnetofrictional modelling (TMFM) of active region magnetic fields has been proven as a tool to observe and study the corona. In this work, we present a detailed study of data-driven TMFM of active region 12473 to trace the early evolution of the flux rope related to the coronal mass ejection that occurred on 28 December 2015. Non-inductive electric field component in the photosphere is critical for energizing and introducing twist to the coronal magnetic field, thereby allowing unstable configurations to be formed. We estimate this component using an approach based on optimizing the injection of magnetic energy. We study the effects of these optimisation parameters on the data driven coronal simulations. By varying the free optimisation parameters, we explore the changes in flux rope formation and their early evolution, as well other parameters, e.g. axial flux, magnetic field magnitude.</p>

scholarly journals When do solar erupting hot magnetic flux ropes form?

2020 ◽  
Vol 642 ◽  
pp. A109 ◽  
Author(s):  
A. Nindos ◽  
S. Patsourakos ◽  
A. Vourlidas ◽  
X. Cheng ◽  
J. Zhang
Keyword(s):  
Magnetic Flux ◽  
Flux Rope ◽  
Flare Activity ◽  
Solar Dynamics Observatory ◽  
Magnetic Flux Ropes ◽  
Morphological Criteria ◽  
Flux Ropes ◽  
Solar Eruptions ◽  
Solar Dynamics ◽  
Mass Ejection

Aims. We investigate the formation times of eruptive magnetic flux ropes relative to the onset of solar eruptions, which is important for constraining models of coronal mass ejection (CME) initiation. Methods. We inspected uninterrupted sequences of 131 Å images that spanned more than eight hours and were obtained by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to identify the formation times of hot flux ropes that erupted in CMEs from locations close to the limb. The appearance of the flux ropes as well as their evolution toward eruptions were determined using morphological criteria. Results. Two-thirds (20/30) of the flux ropes were formed well before the onset of the eruption (from 51 min to more than eight hours), and their formation was associated with the occurrence of a confined flare. We also found four events with preexisting hot flux ropes whose formations occurred a matter of minutes (from three to 39) prior to the eruptions without any association with distinct confined flare activity. Six flux ropes were formed once the eruptions were underway. However, in three of them, prominence material could be seen in 131 Å images, which may indicate the presence of preexisting flux ropes that were not hot. The formation patterns of the last three groups of hot flux ropes did not show significant differences. For the whole population of events, the mean and median values of the time difference between the onset of the eruptive flare and the appearance of the hot flux rope were 151 and 98 min, respectively. Conclusions. Our results provide, on average, indirect support for CME models that involve preexisting flux ropes; on the other hand, for a third of the events, models in which the ejected flux rope is formed during the eruption appear more appropriate.

Modelling coronal mass ejection flux ropes signatures using Approximate Bayesian Computation: applications to Parker Solar Probe

2020 ◽  
Author(s):  
Andreas Weiss ◽  
Christian Möstl ◽  
Teresa Nieves-Chinchilla ◽  
Tanja Amerstorfer ◽  
Erika Palmerio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejection ◽  
Approximate Bayesian Computation ◽  
Flux Rope ◽  
Bayesian Computation ◽  
Abc Algorithm ◽  
Flux Ropes ◽  
Approximate Bayesian ◽  
Mass Ejection

<p>We present an updated three-dimensional coronal rope ejection (3DCORE) model and an associated pipeline that is capable of producing extremely large ensembles of synthetic in-situ magnetic field measurements from simulated coronal mass ejection flux ropes. The model assumes an empirically motivated torus-like flux rope structure that expands self-similarly and contains an embedded analytical magnetic field. Using an Approximate Bayesian computation (ABC) algorithm we validate the model by showing that it is capable of qualitatively reproducing measured flux rope signatures. The ABC algorithm also gives us uncertainty estimates in the form of probability distributions for all model parameters. We show the first results for applying our model and algorithms to coronal mass ejections observed in situ by Parker Solar Probe, specifically the event on 2018 November 12 at 0.26AU, where we attempt to reproduce the measured magnetic field signatures and furthermore reconstruct the global flux rope geometry.</p>

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