scholarly journals Role of coronal mass ejections in the heliospheric Hale cycle

2007 ◽  
Vol 34 (6) ◽  
Author(s):  
M. J. Owens ◽  
N. A. Schwadron ◽  
N. U. Crooker ◽  
W. J. Hughes ◽  
H. E. Spence
Keyword(s):  
Coronal Mass Ejections

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 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.

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

scholarly journals Role of the Coronal Environment in the Formation of Four Shocks Observed without Coronal Mass Ejections at Earth’s Lagrangian Point L1

2020 ◽  
Vol 895 (2) ◽  
pp. 144
Author(s):  
M. Pick ◽  
J. Magdalenić ◽  
N. Cornilleau-Wehrlin ◽  
B. Grison ◽  
B. Schmieder ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Lagrangian Point

The role of rising magnetic tubes in the formation of impulsive coronal mass ejections

2013 ◽  
Vol 57 (11) ◽  
pp. 860-871 ◽  
Author(s):  
V. G. Eselevich ◽  
M. V. Eselevich
Keyword(s):  
Coronal Mass Ejections

scholarly journals Evolution of interplanetary coronal mass ejections and magnetic clouds in the heliosphere

2013 ◽  
Vol 8 (S300) ◽  
pp. 245-254
Author(s):  
Pascal Démoulin
Keyword(s):  
Solar Wind ◽  
Physical Properties ◽  
Coronal Mass Ejections ◽  
Magnetic Measurements ◽  
Flux Rope ◽  
Magnetic Clouds ◽  
The Sun ◽  
Interplanetary Coronal Mass Ejections

AbstractInterplanetary Coronal Mass Ejections (ICMEs), and more specifically Magnetic Clouds (MCs), are detected with in situ plasma and magnetic measurements. They are the continuation of the CMEs observed with imagers closer to the Sun. A review of their properties is presented with a focus on their magnetic configuration and its evolution. Many recent observations, both in situ and with imagers, point to a key role of flux ropes, a conclusion which is also supported by present coronal eruptive models. Then, is a flux rope generically present in an ICME? How to quantify its 3D physical properties when it is detected locally as a MC? Is it a simple flux rope? How does it evolve in the solar wind? This paper reviews our present answers and limited understanding to these questions.

scholarly journals The Two-step Forbush Decrease: A Tale of Two Substructures Modulating Galactic Cosmic Rays within Coronal Mass Ejections

2021 ◽  
Vol 922 (2) ◽  
pp. 216
Author(s):  
Miho Janvier ◽  
Pascal Démoulin ◽  
Jingnan Guo ◽  
Sergio Dasso ◽  
Florian Regnault ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Coronal Mass Ejections ◽  
Forbush Decrease ◽  
Recovery Phase ◽  
Galactic Cosmic Rays ◽  
Space Environment ◽  
Interplanetary Coronal Mass Ejections ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis

Abstract Interplanetary coronal mass ejections (ICMEs) are known to modify the structure of the solar wind as well as interact with the space environment of planetary systems. Their large magnetic structures have been shown to interact with galactic cosmic rays (GCRs), leading to the Forbush decrease (FD) phenomenon. We revisit in the present article the 17 yr of Advanced Composition Explorer spacecraft ICME detection along with two neutron monitors (McMurdo and Oulu) with a superposed epoch analysis to further analyze the role of the magnetic ejecta in driving FDs. We investigate in the following the role of the sheath and the magnetic ejecta in driving FDs, and we further show that for ICMEs without a sheath, a magnetic ejecta only is able to drive significant FDs of comparable intensities. Furthermore, a comparison of samples with and without a sheath with similar speed profiles enable us to show that the magnetic field intensity, rather than its fluctuations, is the main driver for the FD. Finally, the recovery phase of the FD for isolated magnetic ejecta shows an anisotropy in the level of the GCRs. We relate this finding at 1 au to the gradient of the GCR flux found at different heliospheric distances from several interplanetary missions.

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