A simple test of the induced nature of the Martian tail

The cross tail component of the magnetic field in the Mars wake allows a simple test of the contribution of the intrinsic planetary magnetic field to the observed magnetic field. If the magnetic tail is entirely induced, then the direction of this cross tail component should be highly correlated with the direction of the interplanetary magnetic field. It is found that the direction of the cross tail magnetic field is so highly correlated with the direction of the cross flow interplanetary magnetic field that there can be little intrinsic contribution to the Martian magnetotail. This in turn implies that the upper limit to the Martian magnetic moment is about 4 × 1011 Tm3.