Journal of Geophysical Research: Space Physics
American Geophysical Union
We conducted a model study of ground magnetic signatures of traveling convection vortices (TCVs) that included both the ionospheric conductivity enhancement associated with the TCVs and the ground induction effect. We found that the localized conductivity enhancement can cause a significant distortion of the TCV current system and lead to a distortion of the ground magnetic disturbance patterns. The patterns of all three magnetic components are asymmetric, mainly in the E-W direction, and the patterns of the Z component show the strongest asymmetry (20–30%). We also found that the effect of induction currents on ground magnetic signatures of the TCVs is insignificant (less than 5%). The results show that because of the presence of localized conductivity enhancements the polarity and speed of the TCVs can significantly influence the distortion features of ground magnetic patterns. The upward and downward current filaments of a TCV with a clockwise leading convection cell can wrap with each other, resulting in a rotation of the whole ground magnetic disturbance pattern. This rotation feature is most significant when the speed of the TCVs is high.
Zhu, L., P. Gifford, J. J. Sojka, and R. W. Schunk (1997), Model study of ground magnetic signatures of traveling convection vortices, J. Geophys. Res., 102(A4), 7449–7459, doi:10.1029/96JA03682.