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Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
What controls the local time extent of flux transfer events? / Milan, S. E.; Imber, S. M.; Carter, J. A. et al.
In: Journal of Geophysical Research: Space Physics, Vol. 121, No. 2, 01.02.2016, p. 1391-1401.Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - What controls the local time extent of flux transfer events?
AU - Milan, S. E.
AU - Imber, S. M.
AU - Carter, J. A.
AU - Walach, M. T.
AU - Hubert, B.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Flux transfer events (FTEs) are the manifestation of bursty and/or patchy magnetic reconnection at the magnetopause. We compare two sequences of the ionospheric signatures of flux transfer events observed in global auroral imagery and coherent ionospheric radar measurements. Both sequences were observed during very similar seasonal and interplanetary magnetic field (IMF) conditions, though with differing solar wind speed. A key observation is that the signatures differed considerably in their local time extent. The two periods are 26 August 1998, when the IMF had components BZ≈-10 nT and BY≈9 nT and the solar wind speed was VX≈650 km s-1, and 31 August 2005, IMF BZ≈-7 nT, BY≈17 nT, and VX≈380 km s-1. In the first case, the reconnection rate was estimated to be near 160 kV, and the FTE signatures extended across at least 7 h of magnetic local time (MLT) of the dayside polar cap boundary. In the second, a reconnection rate close to 80 kV was estimated, and the FTEs had a MLT extent of roughly 2 h. We discuss the ramifications of these differences for solar wind-magnetosphere coupling.
AB - Flux transfer events (FTEs) are the manifestation of bursty and/or patchy magnetic reconnection at the magnetopause. We compare two sequences of the ionospheric signatures of flux transfer events observed in global auroral imagery and coherent ionospheric radar measurements. Both sequences were observed during very similar seasonal and interplanetary magnetic field (IMF) conditions, though with differing solar wind speed. A key observation is that the signatures differed considerably in their local time extent. The two periods are 26 August 1998, when the IMF had components BZ≈-10 nT and BY≈9 nT and the solar wind speed was VX≈650 km s-1, and 31 August 2005, IMF BZ≈-7 nT, BY≈17 nT, and VX≈380 km s-1. In the first case, the reconnection rate was estimated to be near 160 kV, and the FTE signatures extended across at least 7 h of magnetic local time (MLT) of the dayside polar cap boundary. In the second, a reconnection rate close to 80 kV was estimated, and the FTEs had a MLT extent of roughly 2 h. We discuss the ramifications of these differences for solar wind-magnetosphere coupling.
KW - flux transfer events
KW - magnetic reconnection
U2 - 10.1002/2015JA022012
DO - 10.1002/2015JA022012
M3 - Journal article
AN - SCOPUS:84959378225
VL - 121
SP - 1391
EP - 1401
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9402
IS - 2
ER -