The Complexity of the Heliospheric Magnetic Field: Fisk vs Parker
The Parker (Archimedian) spiral model for the heliospheric magnetic field has proven remarkably successful at all locations reached by spacecraft. There are possible deviations from the Parker result due to the differential rotation of the Sun and to the tilt of the solar magnetic axsis compared to the rotation axis. Len Fisk's model of the heliospheric field takes these effects into account and predicts that the meridional component of the mean field will be nonzero, contrary to the Parker result. This provides a testable prediction of the Fisk model. This talk will present evidence that the measured field is essentially random, thus vindicating Parker yet again. Possible explanations will be explored, including various nonideal conditions at the inner boundary of the flow.