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

1989 ◽  
Vol 104 (1) ◽  
pp. 387-397
Author(s):  
Peter A. Sturrock

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.


2008 ◽  
Vol 4 (S257) ◽  
pp. 271-277
Author(s):  
Bojan Vršnak ◽  
Dijana Vrbanec ◽  
Jaša Čalogović ◽  
Tomislav Žic

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.


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

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

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

2013 ◽  
Vol 8 (S300) ◽  
pp. 245-254
Author(s):  
Pascal Démoulin

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.


2016 ◽  
Vol 12 (S328) ◽  
pp. 218-220
Author(s):  
Carlos Roberto Braga ◽  
Rafael Rodrigues Souza de Mendonça ◽  
Alisson Dal Lago ◽  
Ezequiel Echer

AbstractCoronal mass ejections (CMEs) are the main source of intense geomagnetic storms when they are earthward directed. Studying their travel time is a key-point to understand when the disturbance will be observed at Earth. In this work, we study the CME that originated the interplanetary disturbance observed on 2013/10/02. According to the observations, the CME that caused the interplanetary disturbance was ejected on 2013/09/29. We obtained the CME speed and estimate of the time of arrival at the Lagrangian Point L1 using the concept of expansion speed. We found that observed and estimated times of arrival of the shock differ between 2 and 23 hours depending on method used to estimate the radial speed.


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