A Twisted Flux Rope Model for Coronal Mass Ejections and Two-Ribbon Flares

2000 ◽  
Vol 529 (1) ◽  
pp. L49-L52 ◽  
Author(s):  
T. Amari ◽  
J. F. Luciani ◽  
Z. Mikic ◽  
J. Linker
Keyword(s):  
Coronal Mass Ejections ◽  
Flux Rope

scholarly journals Hydrogen non-equilibrium ionisation effects in coronal mass ejections

2020 ◽  
Vol 637 ◽  
pp. A49
Author(s):  
P. Pagano ◽  
A. Bemporad ◽  
D. H. Mackay
Keyword(s):  
Magnetic Flux ◽  
Visible Light ◽  
Coronal Mass Ejections ◽  
Flux Rope ◽  
Neutral Hydrogen ◽  
Hydrogen Atoms ◽  
Mhd Simulation ◽  
Magnetic Flux Rope ◽  
New Generation ◽  
Non Equilibrium

Context. A new generation of coronagraphs used to study solar wind and coronal mass ejections (CMEs) are being developed and launched. These coronagraphs will heavily rely on multi-channel observations where visible light (VL) and UV-EUV (ultraviolet-extreme ultraviolet) observations provide new plasma diagnostics. One of these instruments, Metis on board ESA-Solar Orbiter, will simultaneously observe VL and the UV Lyman-α line. The number of neutral hydrogen atoms (a small fraction of coronal protons) is a key parameter for deriving plasma properties, such as the temperature from the observed Lyman-α line intensity. However, these measurements are significantly affected if non-equilibrium ionisation effects occur, which can be relevant during CMEs. Aims. The aim of this work is to determine if non-equilibrium ionisation effects are relevant in CMEs and, in particular, when and in which regions of the CME plasma ionisation equilibrium can be assumed for data analysis. Methods. We used a magneto-hydrodynamic (MHD) simulation of a magnetic flux rope ejection to generate a CME. From this, we then reconstructed the ionisation state of hydrogen atoms in the CME by evaluating both the advection of neutral and ionised hydrogen atoms and the ionisation and recombination rates in the MHD simulation. Results. We find that the equilibrium ionisation assumption mostly holds in the core of the CME, which is represented by a magnetic flux rope. In contrast, non-equilibrium ionisation effects are significant at the CME front, where we find about 100 times more neutral hydrogen atoms than prescribed by ionisation equilibrium conditions. We find this to be the case even if this neutral hydrogen excess might be difficult to identify due to projection effects. Conclusions. This work provides key information for the development of a new generation of diagnostic techniques that aim to combine visible light and Lyman-α line emissions. The results show that non-equilibrium ionisation effects need to be considered when we analyse CME fronts. Incorrectly assuming equilibrium ionisation in these regions would lead to a systematic underestimate of plasma temperatures.

scholarly journals Do All Interplanetary Coronal Mass Ejections Have a Magnetic Flux Rope Structure Near 1 au?

2020 ◽  
Vol 901 (2) ◽  
pp. L21
Author(s):  
H. Q. Song ◽  
J. Zhang ◽  
X. Cheng ◽  
G. Li ◽  
Q. Hu ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Coronal Mass Ejections ◽  
Flux Rope ◽  
Interplanetary Coronal Mass Ejections ◽  
Magnetic Flux Rope

scholarly journals Observations of flux rope formation prior to coronal mass ejections

2013 ◽  
Vol 8 (S300) ◽  
pp. 209-214 ◽  
Author(s):  
Lucie M. Green ◽  
Bernhard Kliem
Keyword(s):  
Magnetic Flux ◽  
Magnetic Structure ◽  
Solar Atmosphere ◽  
Coronal Mass Ejections ◽  
Flux Rope ◽  
Active Regions ◽  
Magnetic Configuration ◽  
Magnetic Flux Rope ◽  
Source Regions ◽  
Flux Ropes

AbstractUnderstanding the magnetic configuration of the source regions of coronal mass ejections (CMEs) is vital in order to determine the trigger and driver of these events. Observations of four CME productive active regions are presented here, which indicate that the pre-eruption magnetic configuration is that of a magnetic flux rope. The flux ropes are formed in the solar atmosphere by the process known as flux cancellation and are stable for several hours before the eruption. The observations also indicate that the magnetic structure that erupts is not the entire flux rope as initially formed, raising the question of whether the flux rope is able to undergo a partial eruption or whether it undergoes a transition in specific flux rope configuration shortly before the CME.

The Flux‐Rope Scaling of the Acceleration of Coronal Mass Ejections and Eruptive Prominences

2006 ◽  
Vol 649 (1) ◽  
pp. 452-463 ◽  
Author(s):  
J. Chen ◽  
C. Marque ◽  
A. Vourlidas ◽  
J. Krall ◽  
P. W. Schuck
Keyword(s):  
Coronal Mass Ejections ◽  
Flux Rope

scholarly journals DRIVING CURRENTS FOR FLUX ROPE CORONAL MASS EJECTIONS

2009 ◽  
Vol 693 (2) ◽  
pp. 1219-1222 ◽  
Author(s):  
Prasad Subramanian ◽  
Angelos Vourlidas
Keyword(s):  
Coronal Mass Ejections ◽  
Flux Rope

The Effect of Curvature on Flux‐Rope Models of Coronal Mass Ejections

1998 ◽  
Vol 504 (2) ◽  
pp. 1006-1019 ◽  
Author(s):  
J. Lin ◽  
T. G. Forbes ◽  
P. A. Isenberg ◽  
P. Demoulin
Keyword(s):  
Coronal Mass Ejections ◽  
Flux Rope
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