Dynamics of coronal mass ejections - The mass-scaling of the aerodynamic drag (CROSBI ID 145057)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Vršnak, Bojan ; Vrbanec, Dijana ; Čalogović, Jaša
engleski
Dynamics of coronal mass ejections - The mass-scaling of the aerodynamic drag
Context. Coronal and interplanetary propagation of coronal mass ejections (CMEs) is strongly affected by aerodynamic drag. Aims. The dependence of the drag acceleration on the mass of the CMEs is investigated to establish a quantitative empirical relationship, which might be important in semi-empirical space-weather forecasting. Methods. We employ a large sample of CMEs observed in the radial distance range of 2?30 solar radii by the Large Angle and Spectrometric Coronagraph on board the SoHO mission to statistically analyze the acceleration-velocity relationship in subsamples of various classes of CME masses. Results. It is demonstrated that the slope and the v-axis intercept of the anti-correlation of the CME acceleration a and velocity v depend on the mean mass of CMEs included in the sample. The slope k of the correlation is less steep for subsamples of higher masses, revealing that massive CMEs are less affected by the aerodynamic drag. Furthermore, it is found that the v-axis intercept is shifted to higher velocities for subsamples of higher masses. This indicates that, on average, the driving force is greater in more massive CMEs. Conclusions. The empirically established dependence of the a(v) slope on the CME mass is very close to the dependence which follows from the physical characteristics of the aerodynamic drag.
Sun: coronal mass ejections (CMEs); Sun: corona; Sun: solar wind; magnetohydrodynamics (MHD)
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Podaci o izdanju
490 (2)
2008.
811-815
objavljeno
0935-4956
10.1051/0004-6361:200810215