Prevalence of extended reconnection X-lines in the solar wind at 1 AU

A survey of Wind and ACE data has been performed to address the generality of previous reports of extremely extended reconnection X-lines in the solar wind. We have studied 51 events in which both Wind and ACE detected the same solar wind current sheets and one of the spacecraft observed a reconnection exhaust. In 50 of the 51 events, the other spacecraft also observed essentially the same reconnection signatures, and all but one of the jets pointed in the same direction at both spacecraft. In 7 of these cases, the X-line extended more than 100 Earth radii (or 10 4 ion skin depths). Our findings strongly indicate that reconnection X-lines in large-scale current sheets (with magnetic shear >similar to 70 degrees) are fundamentally extended, and not patchy and randomly distributed in space. Finally, the extended reconnecting current sheets are typically highly planar, indicating no significant current sheet warping associated with the reconnection process. Citation: Phan, T. D., J. T. Gosling, and M. S. Davis (2009), Prevalence of extended reconnection X-lines in the solar wind at 1 AU, Geophys. Res. Lett., 36, L09108, doi:10.1029/2009GL037713.