Publication Date:
2018-07-03
Description:
Magnetic reconnection X-lines can vary considerably in length. At the Earth's magnetopause, the length generally corresponds to the extent in local time. The extent has been probed by multi-spacecraft crossing the magnetopause, but the estimates have large uncertainties because of the assumption of a continuous X-line between spacecraft and the lack of information beyond areas of spacecraft coverage. The extent has also been inferred by radars as fast ionospheric flows moving anti-sunward across the open-closed field line boundary, but whether a particular ionospheric flow results from reconnection needs to be confirmed. To achieve a reliable interpretation, we compare X-line extents probed by multi-spacecraft and radars for three conjunction events. We find that when reconnection is active at only one spacecraft, only the ionosphere conjugate to this spacecraft shows a channel of fast anti-sunward flow. When reconnection is active at two spacecraft and the spacecraft are separated by 10Re) are possible forms of reconnection at the magnetopause. Interestingly, the extended reconnection develops from a localized patch via spreading across local time. Potential effects of IMF Bx and By on the X-line extent are discussed.
Electronic ISSN:
2568-6402
Topics:
Geosciences
,
Physics
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