HR: 1340h
AN: SH13A-0293    [Abstracts]
TI: A Flux-Rope Scaling of CME and Prominence Acceleration
AU: Marque, C
EM: Marque@nrl.navy.mil
AF: Space Science Division, Naval Research Laboratory, Washington, DC 20375
AU: * Chen, J
EM: chen@ppd.nrl.navy.mil
AF: Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375
AU: Vourlidas, A
EM: Vourlidas@nrl.navy.mil
AF: Space Science Division, Naval Research Laboratory, Washington, DC 20375
AU: Krall, J
EM: krall@ppd.nrl.navy.mil
AF: Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375
AU: Schuck, P
EM: schuck@ppd.nrl.navy.mil
AF: Space Science Division, Naval Research Laboratory, Washington, DC 20375
AB: It has been known that coronal mass ejections (CMEs) and eruptive prominences (EPs) are closely associated with each other. A major question concerning CMEs and EPS is the magnetic geometry that underlies the eruptive plasma structures. It is now well established that many CMEs can be explained as erupting magnetic flux ropes. However, the coronal magnetic field cannot be directly measured at this time, and therefore the flux rope hypothesis has not been confirmed by magnetic field data. A second unresolved question is the structural relationship between the closely associated CMEs and EPs. Recently, it was theoretically found [1] that the height at which a CME or an EP attains maximum acceleration scales with the footpoint separation distance (S_f) of the underlying magnetic flux rope. This scaling law is characteristic of an erupting flux rope and is universal in that it depends only the flux rope geometry and the Lorentz force acting on the structure. It was shown to be well satisfied based on comparison with a small number of CMEs and EPs, indicating that the erupting structures in these events were initially flux ropes or evolved into flux ropes early enough. In the present paper, we present results of a study using a larger sample of events. In this study, we have analyzed CME events detected by LASCO, for which footpoints are determined by observational proxies such as magnetic neutral line length, and EPs seen in H_α and radio data, for which footpoint locations are observable. We find that CMEs and EPs in this large sample also satisfy the flux-rope scaling law. The results are consistent with the model structure with the bright CME rim at Z+2a and the prominence at Z-a, where Z is the height of the centroid and a is the minor radius of the flux rope, both defined at the apex of the flux rope.
1. Chen, J. and J. Krall, JGR, 108 (A11), 2003
DE: 7513 Coronal mass ejections (2101)
DE: 7531 Prominence eruptions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005