The Roles of Reconnected Flux and Overlying Fields in CME Speeds

Abstract

Researchers have reported (i) correlations of coronal mass ejection (CME) speeds and the total photospheric magnetic flux swept out by flare ribbons in flare-associated eruptive events, and, separately, (ii) correlations of CME speeds and more rapid decay, with height, of magnetic fields in potential coronal models above eruption sites. Here, we compare the roles of both ribbon fluxes and the decay rates of overlying fields in a set of 16 eruptive events. We confirm previous results that higher CME speeds are associated with both larger ribbon fluxes and more rapidly decaying overlying fields. We find the association with ribbon fluxes to be weaker than a previous report, but stronger than the dependence on the decay rate of overlying fields. Since the photospheric ribbon flux is thought to approximate the amount of coronal magnetic flux reconnected during the event, the correlation of speeds with ribbon fluxes suggests that reconnection plays some role in accelerating CMEs. One possibility is that reconnected fields that wrap around the rising ejection produce an increased outward hoop force, thereby increasing CME acceleration. The correlation of CME speeds with more rapidly decaying overlying fields might be caused by greater downward magnetic tension in stronger overlying fields, which could act as a source of drag on rising ejections.

12 pages, 6 figures, 2 tables; under review

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Cited by in corpus (6)

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• How Does Magnetic Reconnection Drive the Early Stage Evolution of Coronal Mass Ejections?
• Does Nearby Open Flux Affect the Eruptivity of Solar Active Regions?
• The Kinematical Behavior of Solar Eruptive Filaments Affected by the Poloidal Magnetic Field
• Analysis of the Evolution of a Multi-Ribbon Flare and Failed Filament Eruption