Initiation of Coronal Mass Ejections by Magnetic Flux Emergence in the Framework of the Breakout Model

In a few recent studies, 8 coronal mass ejections (CMEs) were identified to associate with a superactive region, AR 8100. They were all flare-CME events, It is found that the region is characterized by vigorous flux emergence and an imbalance of magnetic flux in two polarities. With the continuous flux emergence and its driven flux cancellation, the EUV dimming associated with flare activity increased in area. Whenever the dimming extended to an area of more than 50×50 square degrees on the solar surface, a flare in the region became CME-associated.

Download Full-text

Modelling the initiation of coronal mass ejections: magnetic flux emergence versus shearing motions

Astronomy and Astrophysics ◽

10.1051/0004-6361/200912541 ◽

2009 ◽

Vol 507 (1) ◽

pp. 441-452 ◽

Cited By ~ 29

Author(s):

F. P. Zuccarello ◽

C. Jacobs ◽

A. Soenen ◽

S. Poedts ◽

B. van der Holst ◽

...

Keyword(s):

Magnetic Flux ◽

Coronal Mass Ejections ◽

Flux Emergence

Download Full-text

The initiation of coronal mass ejections by magnetic flux emergence

Astronomy and Astrophysics ◽

10.1051/0004-6361:20054719 ◽

2006 ◽

Vol 459 (3) ◽

pp. 927-934 ◽

Cited By ~ 10

Author(s):

G. Dubey ◽

B. van der Holst ◽

S. Poedts

Keyword(s):

Magnetic Flux ◽

Coronal Mass Ejections ◽

Flux Emergence

Download Full-text

Magnetic Flux Emergence and Shearing Motions as Trigger Mechanisms for Coronal Mass Ejections

10.1063/1.3137949 ◽

2009 ◽

Author(s):

S. Poedts ◽

A. Soenen ◽

F. P. Zuccarello ◽

C. Jacobs ◽

B. van der Holst ◽

...

Keyword(s):

Magnetic Flux ◽

Coronal Mass Ejections ◽

Flux Emergence ◽

Trigger Mechanisms

Download Full-text

Solar Filaments as Tracers of Subsurface Processes

International Astronomical Union Colloquium ◽

10.1017/s0252921100064459 ◽

2000 ◽

Vol 179 ◽

pp. 177-183

Author(s):

D. M. Rust

Keyword(s):

Magnetic Fields ◽

Magnetic Flux ◽

Coronal Mass Ejections ◽

Interplanetary Space ◽

Intermediate Stage ◽

Coronal Plasma ◽

Magnetic Helicity ◽

The Sun ◽

New Paradigm ◽

Solar Filaments

AbstractSolar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields’ sources in the photosphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

Download Full-text

Energetics of magnetic transients in a solar active region plage

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834548 ◽

2019 ◽

Vol 623 ◽

pp. A176 ◽

Cited By ~ 3

Author(s):

L. P. Chitta ◽

A. R. C. Sukarmadji ◽

L. Rouppe van der Voort ◽

H. Peter

Keyword(s):

Magnetic Field ◽

Active Region ◽

Magnetic Flux ◽

Numerical Simulations ◽

Extreme Ultraviolet ◽

Spatial Scales ◽

Coronal Loops ◽

The Sun ◽

Flux Emergence ◽

Transient Events

Context. Densely packed coronal loops are rooted in photospheric plages in the vicinity of active regions on the Sun. The photospheric magnetic features underlying these plage areas are patches of mostly unidirectional magnetic field extending several arcsec on the solar surface. Aims. We aim to explore the transient nature of the magnetic field, its mixed-polarity characteristics, and the associated energetics in the active region plage using high spatial resolution observations and numerical simulations. Methods. We used photospheric Fe I 6173 Å spectropolarimetric observations of a decaying active region obtained from the Swedish 1-m Solar Telescope (SST). These data were inverted to retrieve the photospheric magnetic field underlying the plage as identified in the extreme-ultraviolet emission maps obtained from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). To obtain better insight into the evolution of extended unidirectional magnetic field patches on the Sun, we performed 3D radiation magnetohydrodynamic simulations of magnetoconvection using the MURaM code. Results. The observations show transient magnetic flux emergence and cancellation events within the extended predominantly unipolar patch on timescales of a few 100 s and on spatial scales comparable to granules. These transient events occur at the footpoints of active region plage loops. In one case the coronal response at the footpoints of these loops is clearly associated with the underlying transient. The numerical simulations also reveal similar magnetic flux emergence and cancellation events that extend to even smaller spatial and temporal scales. Individual simulated transient events transfer an energy flux in excess of 1 MW m−2 through the photosphere. Conclusions. We suggest that the magnetic transients could play an important role in the energetics of active region plage. Both in observations and simulations, the opposite-polarity magnetic field brought up by transient flux emergence cancels with the surrounding plage field. Magnetic reconnection associated with such transient events likely conduits magnetic energy to power the overlying chromosphere and coronal loops.

Download Full-text

Simulations of Switchback, Fragmentation and Sunspot Pair in δ-Sunspots during Magnetic Flux Emergence

Sensors ◽

10.3390/s21020586 ◽

2021 ◽

Vol 21 (2) ◽

pp. 586

Author(s):

Che-Jui Chang ◽

Jean-Fu Kiang

Keyword(s):

Magnetic Field ◽

Solar System ◽

Field Strength ◽

Magnetic Flux ◽

Initial Conditions ◽

Observation Data ◽

Flux Emergence ◽

Polarity Inversion ◽

Simulation Results ◽

Spot Type

Strong flares and coronal mass ejections (CMEs), launched from δ-sunspots, are the most catastrophic energy-releasing events in the solar system. The formations of δ-sunspots and relevant polarity inversion lines (PILs) are crucial for the understanding of flare eruptions and CMEs. In this work, the kink-stable, spot-spot-type δ-sunspots induced by flux emergence are simulated, under different subphotospheric initial conditions of magnetic field strength, radius, twist, and depth. The time evolution of various plasma variables of the δ-sunspots are simulated and compared with the observation data, including magnetic bipolar structures, relevant PILs, and temperature. The simulation results show that magnetic polarities display switchbacks at a certain stage and then split into numerous fragments. The simulated fragmentation phenomenon in some δ-sunspots may provide leads for future observations in the field.

Download Full-text