Naslov
Acceleration phase of coronal mass ejections: I. Temporal and spatial scales

Autori
Vršnak, Bojan ; Maričić, Darije ; Stanger, Andrew ; Veronig, Astrid ; Temmer, Manuela ; Roša, Dragan

Izvornik
Solar Physics (0038-0938) 241 (2007), 1; 85-98

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
coronal mass ejections

Sažetak
We study kinematics of 22 coronal mass ejections (CMEs) whose motion was traced from the gradual pre-acceleration phase up to the post-acceleration stage. The peak accelerations in the studied sample range from 40, up to 7000 m\, s$^{;-2};$, and are inversely proportional to the acceleration phase duration and the height range involved. Accelerations and velocities are, on average, larger in CMEs launched from a compact source region. The acceleration phase duration is proportional to the source region dimensions, i.e., compact CMEs are accelerated more impulsively. Such a behavior is interpreted as a consequence of stronger Lorentz force and shorter Alfv\'en time-scales involved in compact CMEs (stronger magnetic field and larger Alfv\'en speed are involved at lower heights). CMEs with larger accelerations and velocities are on average wider, whereas the widths are not related to the source region dimensions. Such behavior is explained in terms of the field pile-up ahead of the erupting structure, which is more effective in the case of a strongly-accelerated structure.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA