The flux-rope scaling of the acceleration of coronal mass ejections and eruptive prominences

The new flux-rope scaling law of the acceleration of coronal mass ejections (CMEs) derived by Chen & Krall is quantitatively tested by comparing the theoretical prediction with the near-Sun acceleration profiles of 13 eruptive prominences (EPs) and four CMEs. A CME and associated EP are assumed to be organized by an underlying magnetic flux rope (MFR) with specific structural and geometrical relationships. The scaling law states that if the initial structure is a flux rope with a footpoint separation distance of S-f, then the height Z(max) at which the acceleration measured at the centroid of the apex reaches maximum scales with S-f. The primary source of prominence data is the radio data from the archive of the Nobeyama Radio Observatory. A number of H alpha events are also included. For CMEs, previously published events with good coverage of the initial acceleration are used. For each event, observed quantities are used to determine S-f and Z(max). It is shown that for the events included in the present study, Zmax scales with Sf in accordance with the scaling law. The result is consistent with the hypothesis that the preeruption magnetic structure underlying a CME and the associated EP is a flux rope driven by the toroidal Lorentz hoop force. The scaling law may constitute a quantitative observable discriminator of the preeruption magnetic geometry underlying CMEs/EPs and the driving force.