North-South Asymmetry of the Sun and the Heliosphere

Vladimir A. Osherovich
RITSS at NASA/GSFC, Greenbelt, Maryland

The existence of a sizable quadrupole component in the global magnetic field of the sun has been proposed fifteen years back (Osherovich, Tzur and Gliner, 1984) as a cause of north-south asymmetry of the solar corona. Observational evidence which includes a 20-30 % difference in the strength of magnetic field measured at the two solar poles support this view (Osherovich et al, 1998). We present evidence that a solar wind quasi-invariant as a new index of solar activity (Osherovich, Fainberg and Stone, 1999) also shows the asymmetry between northern and southern hemispheres reflecting the underlying north-south asymmetry of the solar corona. The phase and amplitude of the quasi-invariant asymmetry and its relation to the global magnetic structure of the heliosphere is the subject of our presentation.

• Osherovich, V A, I Tzur and E B Gliner, Astrophys J., 284, 412-421, 1984
• Osherovich, V A, J Fainberg and R G Stone, Geophys Res Lett, in press, 1999
• Osherovich et al, in Solar Wind 9, Eds S R Habbal, R Esser, J V Hollweg and P A Isenberg, 721-724, 1998