caa a22 4500 445346132 CHVBK 20180317142829.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s11207-011-9722-9 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9722-9 Cyclic Reversal of Magnetic Cloud Poloidal Field [Elektronische Daten] [Y. Li, J. Luhmann, B. Lynch, E. Kilpua] Coronal mass ejections (CMEs) carry magnetic structure from the low corona into the heliosphere. The interplanetary CMEs (ICMEs) that exhibit the topology of helical magnetic fluxropes are traditionally called magnetic clouds (MCs). MC fluxropes with axis of low (high) inclination with respect to the ecliptic plane have been referred to as bipolar (unipolar) MCs. The poloidal field of bipolar MCs has a solar cycle dependence. We report a cyclic reversal of the poloidal field of low inclination MC fluxropes during 1976 to 2009. The MC poloidal field cyclic reversal on the same time scale of the solar magnetic cycle is evident over three sunspot cycles. Approximately 48% of ICMEs are MCs, and 40% of IMCs are bipolar MCs during solar cycle23. The speed of the bipolar MCs has essentially the same distribution as all ICMEs, which implies that they are not from any special type of CMEs in terms of the solar origin. Although CME fluxropes may undergo a number of complications during the eruption and propagation, a significant group of MCs retains sufficient similarity to the source region magnetic field to posses the same cyclic periodicity in polarity reversal. The poloidal field of bipolar MCs gives the out-of-ecliptic-plane field or B z component in the IMF time series. MCs with southward B z field are particularly effective in causing geomagnetic disturbances. During the solar minima, the B z field IMF sequence within MCs at the leading portion of a bipolar MC is the same with the solar global dipole field. Our finding shows that MCs preferentially remove the like polarity of the solar dipole field, and it supports the participation of CMEs in the solar magnetic cycle. The Author(s), 2011 Coronal mass ejection nationallicence Magnetic cloud nationallicence Magnetic field nationallicence Solar cycle nationallicence Solar wind nationallicence Li Y. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut Luhmann J. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut Lynch B. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut Kilpua E. Department of Physics, Division of Atmospheric Sciences and Geophysics, University of Helsinki, Helsinki, Finland aut Solar Physics Springer Netherlands 270/1(2011-05-01), 331-346 0038-0938 270:1<331 2011 270 11207 https://doi.org/10.1007/s11207-011-9722-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9722-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Li Y. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut NATIONALLICENCE 700 1- Luhmann J. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut NATIONALLICENCE 700 1- Lynch B. Space Sciences Laboratory, University of California, Berkeley, CA, USA aut NATIONALLICENCE 700 1- Kilpua E. Department of Physics, Division of Atmospheric Sciences and Geophysics, University of Helsinki, Helsinki, Finland aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 270/1(2011-05-01), 331-346 0038-0938 270:1<331 2011 270 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer