Caveats of the Tsyganenko-Sitnov magnetic field models at distances beyond 10 RE in the flanks

The Tsyganenko and Tsyganenko-Sitnov magnetic field models are used extensively in the magneto-spheric modeling community. These empirically based models use measurements from an extensive list of satellites to modify the earth’s dipole field in response to the contact with the solar wind. Because these models are empirically based, their strengths lie in regions of the magnetosphere where the most satellite measurements are made. The outer flanks of magnetosphere near the terminator are regions of transition between the compressed dayside and the stretched tail. Contour maps of total field strength along with fully three dimensional particle tracings are used to examine the Tsyganenko-Sitnov interpretation of the magnetic field in the flanks. When ions and electrons are traced through these regions, unrealistic paths can occur. As a result, caution must be exercised in the aforementioned regions when using these models, as unrealistic magnetic field topologies, and consequently unrealistic particle trajectories, may arise.