HR: 12:05h
AN: SH22A-08    [Abstracts]
TI: Magnetic Geometry of Accelerating CMEs
AU: * Chen, J
EM: chen@ppd.nrl.navy.mil
AF: Plasma Physics Division, Naval Research Laboratory, Code 6790, Washington, DC 20375
AU: Krall, J
EM: krall@ppd.nrl.navy.mil
AF: Plasma Physics Division, Naval Research Laboratory, Code 6790, Washington, DC 20375
AB: It has been known that the main acceleration phase of a coronal mass ejection (CME) is localized to within 3--4 Rs of the Sun. Recently, it has been theoretically shown [1] that if the initial structure is a magnetic flux rope, the main acceleration peaks at apex height $Z_* \approx S_f/2$, where $S_f$ is the separation distance between the two footpoints anchored in the photosphere. This scaling property is therefore an observational signature of the magnetic geometry. The $S_f$-scaling law is universal in that it only depends on the pre-eruptive flux-rope geometry in 3-D. The initial comparisons with representative LASCO CMEs (C1-C2-C3 data) showed that this prediction is consistent with observations [1]. We will present further model-data comparisons using the archived LASCO data as well as eruptive prominence data. We discuss the significant improvement in theory-data comparison that will be possible with the expected STEREO data. Particularly, the two observing perspectives will allow one to better constrain the flux-rope geometry during the main acceleration phase, especially with respect to the footpoint separation $S_f$. In addition, the near-Sun observing capabilities (down to $\sim$0.5 $R_s$) and high cadence of COR1 will provide much better resolved observations of the initial acceleration of CMEs. \medskip 1.~Chen, J., and J. Krall, JGR, 108, 1410, doi:10.1029/2003JA009849, 2003. \medskip Work supported by ONR and NASA
DE: 7513 Coronal mass ejections
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting