The role of aerodynamic drag in dynamics of coronal mass ejections (CROSBI ID 149087)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Vršnak, Bojan ; Vrbanec, Dijana ; Čalogović, Jaša ; Žic, Tomislav
engleski
The role of aerodynamic drag in dynamics of coronal mass ejections
Dynamics 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.
Sun: coronal mass ejections (CMEs); Sun: corona; (Sun:) solar wind; (Sun:) solar-terrestrial relations; (magnetohydrodynamics:) MHD
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Podaci o izdanju
Volume 257
2009.
271-277
objavljeno
1743-9213
1743-9221
10.1017/S1743921309029391
Povezanost rada
Fizika