Interhemispheric magnetic conjugacy

The concept of the inter‐hemispheric magnetic conjugacy was investigated by comparing the conjugate points in the northern and southern hemispheres using the Tsyganenko T02 magnetic field model together with the International Geomagnetic Reference Field model for the internal magnetic field to follow the magnetic field lines. We studied the influence of the dipole tilt angle, solar wind (solar wind dynamic pressure and flow direction), and interplanetary magnetic field (IMF) parameters (IMF B y and B z ) on the latitudinal and longitudinal differences between the foot points of magnetic field lines in both hemispheres. It was found that the dominant difference up to 30° is longitudinal, while latitudinal differences are about 2°. The largest differences are observed at dawn and dusk magnetic local times (MLTs) for large dipole tilt angles during high solar wind dynamic pressure (16–20 nPa) and large IMF B y values ( − 15 and 15 nT). The asymmetry of conjugate points is present due to nonzero values of IMF B y , but there is no real dependence on the magnitude of IMF B y . The influence of IMF B z on the interhemispheric conjugacy depends on the sign of the IMF B z but not much on the magnitude. The rotation of the tail current sheet from the Sun‐Earth line by several degrees resulted in latitudinal differences of 1° and longitudinal differences of 15° at dawn and dusk MLTs for equinox. Testing the concept of magnetic conjugacy with previously reported auroral event observed at Tjörnes (Iceland) and Syowa (Antarctica) observatories confirmed the importance of taking into account the solar wind flow direction, especially when it deviates from radial by more than 2°