scholarly journals The Role of Magnetic Helicity in Coronal Mass Ejections

2005 ◽  
Vol 624 (2) ◽  
pp. L129-L132 ◽  
Author(s):  
A. D. Phillips ◽  
P. J. MacNeice ◽  
S. K. Antiochos
Keyword(s):  
Coronal Mass Ejections ◽  
Magnetic Helicity

Solar Filaments as Tracers of Subsurface Processes

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.

Energetics of Coronal Mass Ejections: Role of the Streamer Cavity

1998 ◽  
Vol 499 (1) ◽  
pp. 496-503 ◽  
Author(s):  
Richard Wolfson ◽  
Siddharth Saran
Keyword(s):  
Coronal Mass Ejections

scholarly journals Magnetic Field Confinement in the Corona: The Role of Magnetic Helicity Accumulation

2006 ◽  
Vol 644 (1) ◽  
pp. 575-586 ◽  
Author(s):  
Mei Zhang ◽  
Natasha Flyer ◽  
Boon Chye Low
Keyword(s):  
Magnetic Field ◽  
Magnetic Helicity

scholarly journals Trend of photospheric magnetic helicity flux in active regions generating halo coronal mass ejections

2010 ◽  
Vol 521 ◽  
pp. A56 ◽  
Author(s):  
A. Smyrli ◽  
F. Zuccarello ◽  
P. Romano ◽  
F. P. Zuccarello ◽  
S. L. Guglielmino ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Active Regions ◽  
Magnetic Helicity

scholarly journals The Role of Eruption in Solar Flares

1989 ◽  
Vol 104 (1) ◽  
pp. 387-397
Author(s):  
Peter A. Sturrock
Keyword(s):  
Energy Release ◽  
Solar Atmosphere ◽  
Coronal Mass Ejections ◽  
Solar Flares ◽  
Thought Experiments ◽  
Physical Behavior ◽  
Current Interruption ◽  
Flare Process ◽  
Plasma Configuration

AbstractThis article focuses on two problems involved in the development of models of solar flares. The first concerns the mechanism responsible for eruptions, such as erupting filaments or coronal mass ejections, that are sometimes involved in the flare process. The concept of ‘loss of equilibrium’ is considered and it is argued that the concept typically arises in thought-experiments that do not represent acceptable physical behavior of the solar atmosphere. It is proposed instead that such eruptions are probably caused by an instability of a plasma configuration. The instability may be purely MHD, or it may combine both MHD and resistive processes. The second problem concerns the mechanism of energy release of the impulsive (or gradual) phase. It is proposed that this phase of flares may be due to current interruption, as was originally proposed by Alfvén and Carlqvist. However, in order for this process to be viable, it seems necessary to change one's ideas about the heating and structure of the corona in ways that are outlined briefly.

scholarly journals The role of aerodynamic drag in dynamics of coronal mass ejections

2008 ◽  
Vol 4 (S257) ◽  
pp. 271-277
Author(s):  
Bojan Vršnak ◽  
Dijana Vrbanec ◽  
Jaša Čalogović ◽  
Tomislav Žic
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Coronal Mass Ejections ◽  
Weather Forecasting ◽  
Aerodynamic Drag ◽  
Interplanetary Space ◽  
Solar Wind Speed ◽  
Standard Form ◽  
The Sun

AbstractDynamics of coronal mass ejections (CMEs) is strongly affected by the interaction of the erupting structure with the ambient magnetoplasma: eruptions that are faster than solar wind transfer the momentum and energy to the wind and generally decelerate, whereas slower ones gain the momentum and accelerate. Such a behavior can be expressed in terms of “aerodynamic” drag. We employ a large sample of CMEs to analyze the relationship between kinematics of CMEs and drag-related parameters, such as ambient solar wind speed and the CME mass. Employing coronagraphic observations it is demonstrated that massive CMEs are less affected by the aerodynamic drag than light ones. On the other hand, in situ measurements are used to inspect the role of the solar wind speed and it is shown that the Sun-Earth transit time is more closely related to the wind speed than to take-off speed of CMEs. These findings are interpreted by analyzing solutions of a simple equation of motion based on the standard form for the drag acceleration. The results show that most of the acceleration/deceleration of CMEs on their way through the interplanetary space takes place close to the Sun, where the ambient plasma density is still high. Implications for the space weather forecasting of CME arrival-times are discussed.

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