Development of a current sheet in the wake of a fast coronal mass ejection

Polarization brightness images from the Mk4 K-Coronameter at the Mauna Loa Solar Observatory are used to determine the structure of the ray along its axis low in the corona as it progressed outward.

Coverage of the early development of the ray out to ~1.3 R ☉ for a period of ~27 hr after the start of the event enables for the first time in white light a measurement of a CME CS from the top of the arcade to the base of the flux rope. Measured widths of the ray are combined to obtain the kinematics of the upper and lower "Y"-points described in reconnection flux-rope models such as that of Lin & Forbes. The time dependence of these points are used to derive values for the speed and acceleration of the growth of the CS.