Polar cap convection relationships with solar wind


  • J. W. MacDougall,

  • P. T. Jayachandran


Relationships between the speed of polar cap antisunward convection and the southward component of the interplanetary magnetic field (IMF Bz negative), and also the induced solar wind electric field (VswBz) are derived from polar cap convection measurements using Canadian Advanced Digital Ionosondes at Eureka (CGM latitude 88.67°N) and Resolute Bay (CGM latitude. 83.55°N). The relationships are similar for Eureka and Resolute Bay, which are separated by ∼600 km, showing that as a first approximation, one can assume uniform polar cap convection. Resolute Bay, however, appeared to show some saturation at IMF Bz values less than approximately −10 nT. The average relationships are as follows: Vconv (m/s) ≈ 294 – 66Bz (nT), and Vconv (m/s) ≈ 293 – 166VswBz (mV/m). The convection speed did not show a significant dependence on the IMF By and Bx components. The amplification factor between the induced solar wind electric field and ionospheric electric field is ∼8.