HR: 16:00h
AN: SH34A-01    [Abstracts]
TI: Hemispherical and Longitudinal Asymmetries in the Heliospheric Magnetic Field: Flip-flops of a Bashful Ballerina
AU: Hiltula, T
EM: teemu.hiltula@oulu.fi
AF: University of Oulu, Linnanmaa, Oulu, 90014 Finland
AU: * Mursula, K
EM: kalevi.mursula@oulu.fi
AF: University of Oulu, Linnanmaa, Oulu, 90014 Finland
AB: Several studies during many decennia have studied possible longitudinal and hemispherical asymmetries in various forms of solar activity. E.g., there are well known periods when one of the solar hemispheres has dominated the other in sunspot numbers, flare occurrence or some other form of solar activity. However, the solar asymmetries have not been found to be very conclusive, or to form any clear systematical patterns (e.g., relation to solar cycle). On the contrary, recent studies of similar longitudinal and hemispherical asymmetries in the heliospheric magnetic field have shown a very clear and systematic behaviour. E.g., it was found recently that the dominance of the two HMF sectors experiences an oscillation with a period of about 3.2 years. This new flip-flop periodicity in the heliospheric magnetic field is most likely related to a similar periodicity recently found in sunspots. Also, it has recently been found that the HMF sector coming from the northern solar hemisphere systematically dominates at 1AU during solar minimum times. This leads to a persistent southward shift or coning of the heliospheric current sheet at these times that can be picturesquely described by the concept of a Bashful Ballerina. This result also implies that the Sun has a large-scale quadrupole magnetic moment. Here we review these recent developments concerning the longitudinal and hemispherical asymmetries in the heliospheric magnetic field and study their inter-connection.
DE: 2134 Interplanetary magnetic fields
DE: 2162 Solar cycle variations (7536)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting